Desolvation process and surface characterisation of protein nanoparticles

The objective of the present study was to characterise and optimise the desolvation process of human serum albumin (HSA) for the preparation of nanoparticles and to characterise the resulting colloidal system. Following the desolvation of the protein, the resulting nanoparticles were stabilised by the addition of varying amounts of glutaraldehyde or by heat denaturation. The particle size, zeta potential, and the number of available amino groups on the surface of the nanoparticles were determined. The amino groups were quantified by a spectrophotometric method using 2,4, 6-trinitrobenzenesulfonic acid (TNBS). The results indicated that the particle size depended mainly on the amount of desolvating agent added, but not on the amount of cross-linker or the kind of cross-linking procedure. Increasing amounts of glutaraldehyde reduced the number of amino groups on the surface of HSA nanoparticles and also decreased the zeta potential of the carrier system. The temperature and heat denaturation time only had an influence on the stability of the nanoparticles but not on the amount of amino groups or the particle size. It was shown that heat denatured HSA nanoparticles possessed the greatest number of amino groups on their surface. Additional experiments for the characterisation of gelatin A and B nanoparticles were performed.

Simple and efficient method for the detection of diethylenetriaminepentaacetic acid

Diethylenetriaminepentaacetic acid (DTPA) is a commonly used chelating agent. Its antiviral, antibacterial and immunomodulatory effects are well documented. DTPA forms a highly stable complex with lead (II) with an increased absorption coefficient and a bathochromic shift of the absorption maximum compared to pure DTPA. Based on this complex a high-performance liquid chromatographic method for the quantitative detection of DTPA in biological fluids was developed. A calibration curve was prepared and linearity was shown in the concentration range between 10 mg l(-1) and 1000 mg l(-1) DTPA. The recovery in water and in human plasma showed the method to be suitable for routine use.

Evidence of altered homocysteine metabolism in chronic renal failure

The fasting serum concentrations of total homocysteine and metabolites of transsulfuration (cystathionine, cysteine, methylmalonic acid, 2-methylcitric acid) and remethylation (methionine) were determined by gas chromatography-mass spectrometry in 40 nondialyzed patients with chronic renal disease and in 50 patients with end-stage renal disease requiring chronic maintenance hemodialysis. The nondialyzed patients and 28 of the dialysis patients did not receive additional vitamin supplementations. Twenty-two of the dialysis patients received daily oral vitamin preparations containing 10 mg pyridoxine (vitamin B(6)), 6 microg cyanocobalamin (vitamin B(12)), and 1 mg folic acid. In the nondialyzed patients, linear regression analysis showed positive correlations between serum concentrations of creatinine and total homocysteine (r = 0.68, p < 0.0001), cystathionine (r = 0.73, p < 0. 0001), methylmalonic acid (r = 0.77, p < 0.0001), and 2-methylcitric acid (r = 0.81, p < 0.0001). Serum homocysteine was positively correlated with serum concentrations of cystathionine (r = 0.59, p < 0.0001), cysteine (r = 0.69, p = 0.004), methylmalonic acid (r = 0. 64, p = 0.0001), and 2-methylcitric acid (r = 0.64, p < 0.0001). There was no significant correlation between serum concentrations of homocysteine and methionine (r = -0.14, p = 0.63). In the hemodialysis patients receiving oral vitamin supplementation, serum homocysteine and cystathionine concentrations were significantly lower than in hemodialysis patients not receiving vitamins (homocysteine 21.8 +/- 1.1 vs. 33.2 +/- 3.7 micromol/l, p = 0.0004; cystathionine 2,075.9 +/- 387.1 vs. 3,171.3 +/- 680.2 nmol/l, p = 0. 02; mean +/- SEM). In summary, our results show increased intermediate products of the transsulfuration pathway, but no increase in remethylation of homocysteine in chronic renal disease, including end-stage renal disease requiring chronic maintenance dialysis.

[The delivery of loperamide to the brain by using polybutyl cyanoacrylate nanoparticles]

The possibility of using polysorbate 80-coated nanoparticles for the delivery of the water insoluble opioid (lyonist loperamide across the blood-brain barrier was investigated. The analgesic effect after i.v. injection of the preparations was used as the indication of drug transport through this barrier. Intravenous injection of the particulate formulation resulted in a long and significant analgesic effect. A polysorbate 80 loperamide solution induced a much less pronounced and very short analgesia. Uncoated nanoparticles loaded with loperamide were unable to produce analgesia. Polysorbate 80-coated PBCA nanoparticles loaded with loperamide led to the transport of loperamide to the brain.

Quantitative colorimetric and gas chromatographic determination of arecaidine propargyl ester

Arecaidine propargyl ester (APE) is a potent muscarinic agonist often used in pharmacological studies. To date, no sensitive quantitative analytical method for APE has been published. In this study, two methods for the quantitative determination of APE are compared: a colorimetric assay, based on the formation of the corresponding ferric(III)-hydroxamic acid complex, and a direct gas chromatographic method, using arecoline as the internal standard. The latter method was found to be more precise. The utility of the gas chromatographic assay was further demonstrated in a stability study of the drug in the biological fluid aqueous humor of rabbits.

Delivery of loperamide across the blood-brain barrier with polysorbate 80-coated polybutylcyanoacrylate nanoparticles

PURPOSE

The possibility of using polysorbate 80-coated nanoparticles for the delivery of the water insoluble opioid agonist loperamide across the blood-brain barrier was investigated. The analgesic effect after i.v. injection of the preparations was used to indicate drug transport through this barrier.

METHODS

Loperamide was incorporated into PBCA nanoparticles. Drug-containing nanoparticles were coated with polysorbate 80 and injected intravenously into mice. Analgesia was then measured by the tail-flick test.

RESULTS

Intravenous injection of the particulate formulation resulted in a long and significant analgesic effect. A polysorbate 80 loperamide solution induced a much less pronounced and very short analgesia. Uncoated nanoparticles loaded with loperamide were unable to produce analgesia.

CONCLUSIONS

Polysorbate 80-coated PBCA nanoparticles loaded with loperamide enabled the transport of loperamide to the brain.

Development of an intravenous glutamine supply through dipeptide technology

Glutamine is considered as semi-essential amino acid during catabolic stress. Due to its chemical instability in aqueous solutions during heat sterilization and long term storage, it could not be added to infusion solutions so far. In contrast, the dipeptide glycl-L-glutamine exhibits all properties needed for use as glutamine derivative in parenteral nutrition. It is freely soluble in water and does not decompose during heat sterilization. The peptide undergoes rapid enzymatic hydrolysis after infusion. This results in perfect utilization. Glycyl-L-glutamine is already produced in large amounts by chemical synthesis techniques. Both chemical and optical purity of the dipeptide can be controlled by modern chromatographic methods. Glamin, a newly developed complete amino acid solution, contains 20 g of glutamine per liter in form of glycyl-L-glutamine. Since no additional free glycine is added, no imbalances are created by the amino-terminal amino acid of the peptide structure.

Ultrastructural study of the dermal microvasculature in patients undergoing retrograde intravenous pressure infusions

BACKGROUND

Retrograde intravenous pressure infusion (RIPI) of drugs, e.g. antibiotics, under arterial occlusion (Bier's block) allows high local tissue concentrations in the extremities. This technique is of particular value in the antibiotic treatment of infected diabetic foot lesions.

OBJECTIVE

The aim of our study was to look for morphological changes of the dermal microvasculature induced by RIPI.

METHODS

In 7 patients with infected diabetic foot lesions, punch biopsies were taken from the calf skin before and at the end of RIPI and studied by light and electron microscopy.

RESULTS

RIPI induced a dilatation of venous capillaries and postcapillary venules, loosening of contacts between endothelial cells (EC) with focal formation of small gaps in the vessel wall and a widening of the space between EC and pericytes. Lymphatic vessels were markedly dilated. In contrast, arterioles did not exhibit signs of morphological alteration. RIPI did not produce cellular damage of blood and lymphatic vessels.

CONCLUSIONS

The morphological changes of dermal vessels induced by RIPI are presumably due to a rapid rise in venous pressure. Our morphological observations support results of previous hemodynamic and nuclear medical investigations, which showed that RIPI enhances the filtration and diffusion of molecules into the interstitium, leading to high local tissue concentrations. The venous capillaries and postcapillary venules are involved in this process in particular.

Hyperhomocysteinemia and the risk for vascular disease in hemodialysis patients

The objective of this study was to examine if hyperhomocysteinemia is associated with occlusive vascular disease in hemodialysis patients. The study design included risk factor analysis and determination of serum homocysteine in hemodialysis patients. Fifty chronic uremic patients on regular hemodialysis treatment were studied. Twenty-four patients had coronary, cerebral, or peripheral signs of occlusive vascular disease. Cerebral vascular disease was diagnosed by computed tomography, arterial angiography, or Doppler sonography of the carotid and vertebral arteries. Coronary vascular disease was diagnosed by documented history of myocardial infarction or by coronary angiography. The diagnosis of peripheral vascular disease was established by angiography of the lower limb arteries. In all control patients, Doppler sonography of the carotid, vertebral, and lower limb arteries and thallium-201 exercise imaging were without pathologic results. Measurements included blood pressure, body mass index, smoking behavior, serum homocysteine (measured by gas chromatography/mass spectrometry), serum total, low-density lipoprotein, and high-density lipoprotein cholesterol, lipoprotein (a), triglycerides, and plasma fibrinogen. In a stepwise multiple logistic regression analysis, high serum homocysteine was significantly associated with occlusive arterial disease (R = 0.23; P = 0.031). Furthermore, hypertension (R = 0.18; P = 0.058), but not serum total, low-density lipoprotein, and high-density lipoprotein cholesterol, lipoprotein (a), triglycerides, diabetes mellitus, body mass index, plasma fibrinogen, and smoking behavior, was significantly associated with atherosclerosis. Our results support the hypothesis that hyperhomocysteinemia is an independent risk factor for vascular disease in hemodialysis patients.

Expression of MHC class II antigens on rat bone marrow cells and macrophages, and their modulation during culture with murine GM-CSF or M-CSF

Flow cytometric analysis employing MRC OX 6 and MRC OX17 monoclonal antibodies recognizing determinants on RT1.B or RT1.D molecules, equivalent to murine I-A and I-E, respectively, was used to detect rat MHC class II antigen (Ag) expression. Approximately 5% of freshly isolated rat bone marrow cells (BMC) expressed RT1.B and over 30% displayed RT1.D molecules. The RT1.D+ cells were W3/13+, OX 7+, OX 19- and OX 22-. After one week culture of BMC with murine recombinant granulocyte/macrophage colony-stimulating factor (GM-CSF), regardless of concentrations, 90 to 95% of the cells were scored as bone marrow-derived macrophages (BMDM phi), and over 30% expressed both RT1.B and RT1.D Ag. GM-CSF increases the percentage of BMDM phi bearing MHC class II Ag in a concentration-dependent manner. This effect seems to be specific because antibodies to interferon-gamma, tumor necrosis factor-alpha or interleukin-4 did not reduce the number of cells expressing RT1.B and RT1.D Ag. Furthermore, GM-CSF was able to trigger expression of class II molecules on rat peritoneal macrophages (M phi) and BMDM phi resulted from cultures of BMC with mouse M phi-CSF (M-CSF), and the RT1.B and RT1.D inducing effect of GM-CSF was opposed by M-CSF, and by anti-GM-CSF antibodies. The induction of MHC class II Ag synthesis by GM-CSF on rat BMDM phi was confirmed at the mRNA level by Northern blot analysis employing cDNA probes encoding the RT1.B alpha.

Amino acid solutions for premature neonates during the first week of life: the role of N-acetyl-L-cysteine and N-acetyl-L-tyrosine

Tyrosine and cyst(e)ine are amino acids that are thought to be essential for preterm neonates. These amino acids have low stability (cyst(e)ine) or low solubility (tyrosine) and are therefore usually present only in small amounts in amino acid solutions. Acetylation improves the stability and solubility of amino acids, facilitating a higher concentration in the solution. We compared three commercially available amino acid solutions, Aminovenös-N-päd 10%, Vaminolact 6.5%, and Primène 10%, administered to 20 low-birth-weight neonates on total parenteral nutrition from postnatal day 2 onward. Aminovenös-N-päd 10% contains acetylated tyrosine and acetylated cysteine; the other solutions do not contain acetylated amino acids and differ in the amount of tyrosine and cysteine added. On postnatal day 7, plasma amino acids were measured together with urinary excretion of amino acids and the total nitrogen excretion; 38% of the intake of N-acetyl-L-tyrosine and 53% of the intake of N-acetyl-L-cysteine were excreted in urine. Plasma levels of N-acetyl-L-tyrosine (331 +/- 74 mumol/L) and N-acetyl-L-cysteine (18 +/- 29 mumol/L) were higher than those of tyrosine (105 +/- 108 mumol/L) and cystine (11 +/- 9 mumol/L), respectively. Plasma tyrosine levels in the groups receiving small amounts of tyrosine remained just below the reference range. We show a linear correlation of plasma cystine with the intake of cysteine (r = .75, p = 0.01), but not with N-acetyl-L-cysteine. The estimated intake of cysteine should be 500 mumol.kg-1.d-1 in order to obtain levels comparable with those shown in normal term, breast-fed neonates. Nitrogen retention did not differ among the three groups (247 to 273 mg.kg-1.d-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Pigmented clear cell acanthoma

We present five cases of macroscopically pigmented clear cell acanthomas. Masson-Fontana silver stain revealed dendritic melanocytes containing melanin granules in large numbers interspersed among the tumoral keratinocytes. The dendritic cells expressed S-100 protein. Electromicroscopy, performed on one pigmented clear cell acanthoma, showed melanosomes in large numbers in the dendrites of melanocytes; whereas only a few melanosomes were found in the adjacent keratinocytes, indicating a disturbed melanin transfer. We propose the name "pigmented clear cell acanthoma" for this variant of Degos' acanthoma.

The role of the physical therapist in hospice care

The role of the physical therapist in hospice care is different from the role the therapist plays when a member of a rehabilitation team. This article will address the need for a fundamental role change and offer suggestions for ways physical therapists can contribute to the care of the hospice patient. In working with hospice patients, therapists must, for the most part, change from a controlling role to one of listener and problem-solver. In this manner, therapists can: Assist the patient to maintain functional abilities for as long as possible; Reduce the burden of care for the caregivers; Assist in pain control. Physical therapists can provide hospice nurses with valuable assistance in caring for hospice patients.

Hyperkeratosis lenticularis perstans (Flegel's disease). Ultrastructural study of lesional and perilesional skin and therapeutic trial of topical tretinoin versus 5-fluorouracil

Lesional and perilesional skin samples from a 57-year-old man who had hyperkeratosis lenticularis perstans (HLP) (Flegel's disease) were studied by light and electron microscopic examination. Keratohyalin granules were diminished at the center of a fully-developed lesion. In contrast, keratohyalin appeared normal and membrane-coating granules were found in reduced numbers at the edges of the HLP lesion and were easily detected in normal numbers in clinically normal, perilesional skin. The inflammatory infiltrate in the HLP lesion was composed of small lymphocytes, which often displayed nuclei with deep infoldings resembling Sézary cells, and larger histiocytic cells, many of which were in close contact with the lymphocytes. Peripheral blood mononuclear cells did not show an abnormal ultrastructural appearance. Treatment with topical 5-fluorouracil cream led to the disappearance of the HLP lesions, whereas topical tretinoin was ineffective.

A new central supply system as alternative source for bicarbonate dialysate

Bicarbonate dialysis is mandatory for high efficiency treatment. In most cases bicarbonate is delivered either as prepacked powder or as a stable liquid concentrate in 6-10 I plastic containers. With a newly designed central supply system (CSS) using 800 I tanks of custom-made sterile and pyrogen free concentrates, we investigated the risk of bacterial contamination of dialysate in a 30-bed dialysis unit. During three months, samples of reverse osmosis (RO) water, concentrates and dialysate were taken every two weeks. Colony forming units (CFU) were counted after 48 h incubation. Further samples were taken during nine months of continuous use of the CSS without further intermittent disinfection. None of the samples had greater than 10/ml CFU. Pseudomonas, corynebacteria and enterobacter were the predominant species. In summary, this CSS proved reliable in providing bacteriologically safe bicarbonate dialysate as defined by international standards (CFU less than 200/ml). It significantly reduces costs, workload and environmental pollution by plastic waste.

A New Central Supply System as Alternative Source for Bicarbonate Dialysate

Bicarbonate dialysis is mandatory for high efficiency treatment. In most cases bicarbonate is delivered either as prepacked powder or as a stable liquid concentrate in 6-10 I plastic containers. With a newly designed central supply system (CSS) using 800 I tanks of custom-made sterile and pyrogen free concentrates, we investigated the risk of bacterial contamination of dialysate in a 30-bed dialysis unit. During three months, samples of reverse osmosis (RO) water, concentrates and dialysate were taken every two weeks. Colony forming units (CFU) were counted after 48 h incubation. Further samples were taken during nine months of continuous use of the CSS without further intermittent disinfection. None of the samples had > 10/ml CFU. Pseudomonas, corynebacteriae and enterobacter were the predominant species. In summary, this CSS proved reliable in providing bacteriologically safe bicarbonate dialysate as defined by international standards (CFU < 200/ml). It significantly reduces costs, workload and environmental pollution by plastic waste.

[Collodion baby with transition to mild lamellar ichthyosis.Clinical course, histopathology and ultrastructural findings]

The case of a collodion baby in whom the condition evolved into a mild form of lamellar ichthyosis is presented. The clinical course was impressive: the hard, collodion-like horny membrane started to crack soon after the birth and had detached completely at the 9th day of life; after a few more days, almost complete clearing of the skin had occurred. At the age of 10 months, the child had only a very mild lamellar ichthyosis. Whereas light microscopy revealed only compact hyperkeratosis on the 1st day of life, electron microscopy suggested a favourable prognosis even at this early stage, which has been corroborated by the ensuing clinical course.

[Long-term results following kidney transplantation. An empirical analysis of 467 allogeneic kidney transplants concerning the effect of clinical and immunological variables on graft function]

In a homogeneous group of 467 cadaver kidney transplants performed within one single center between 1979 and 1987, we analysed the influence of main risk factors on long-term survival up to 72 months. Calculating survival rates by Kaplan-Meier actuarial methods the overall graft survival exceeded 71%. The corresponding patient survival was higher than 90%. A good HLA-A-B and DR match was of significant positive influence. Patients who received cyclosporine had a significant better outcome compared to conventional immunosuppressive therapy. A marked advantage was demonstrated for such variables as number of pretransplant blood transfusions, number of rejection episodes, preservation time and renal function as measured by plasma creatinine. Independently age was a main risk factor for curtailed graft survival. Although immunological factors accounted for more than 45% of transplant loss we found a surprisingly high percentage of infections (36%). Vascular problems or technical failure were below 10%. We conclude that a profound clinical examination in the pretransplant period is of high value and remains necessary to identify high risk patients in the long range.

Cyclosporin A in combination with photochemotherapy (PUVA) in the treatment of psoriasis

Forty patients with relapsing plaque psoriasis involving more than 20% body surface were treated either with cyclosporin A (CyA) plus PUVA or the retinoid etretinate plus PUVA (RePUVA). They initially received either CyA (2 weeks) or etretinate (1 week) alone and then PUVA was given concomitantly until complete remission. The patients were monitored over a period of 6 months and any relapse recorded. With each combined treatment regimen, CyA plus PUVA and RePUVA, the patients cleared within comparable periods of time (mean treatment period of 5.3 vs. 4.7 weeks after initiation of therapy and 3.3 vs. 3.7 weeks after initiation of PUVA). However, the cumulative UVA dose required for clearance (110.9 J/cm2 vs. 62.1 J/cm2 (P less than 0.05)) and the incidence of severe and early relapses were significantly higher in the CyA cohort. Within 6 months severe relapses had occurred in 58% of CyA plus PUVA but only in 15% of RePUVA-treated patients (P less than 0.001). This suggests that the CyA plus PUVA regimen as performed in this study is less effective than RePUVA.

The ultrastructure of dysplastic naevi: comparison with superficial spreading melanoma and common naevocellular naevi

Eleven dysplastic melanocytic naevi with various degrees of dysplasia, as judged by light microscopy, were studied by transmission electron microscopy, and their intra-epidermal melanocytes compared with those of five superficial spreading melanomas and seven common benign naevocellular naevi. Intra-epidermal melanocytes in dysplastic naevi exhibited signs of cellular atypia, which were most pronounced in the dysplastic naevi with histological high-grade dysplasia. A correlation between the degree of dysplasia at the light microscopic level and the degree of cytological atypia at the ultrastructural level was noted, and melanocytes in dysplastic naevi with a high degree of dysplasia had ultrastructural features similar to the melanocytes in superficial spreading melanomas. Our observations support the concept that dysplastic naevi fill the biological gap between benign naevocellular naevi and malignant melanomas and suggest that at least some of the dysplastic naevi must be regarded as potential precursor lesions of malignant melanoma, particularly those exhibiting a high degree of histological dysplasia.

[Histology of the skin and mucous membrane manifestations of AIDS]

The dermatopathologist must be aware of the wide spectrum of non-specific cutaneous manifestations, cutaneous infections and skin tumors associated with AIDS. We present the histological criteria essential for the diagnosis of early Kaposi's sarcoma, its differential diagnosis including epithelioid angiomatosis, as well as the diagnosis of oral hairy leucoplakia.

Keratitis, ichthyosis and deafness (KID)-syndrome: report of three cases and a review of the literature

We report three patients with keratitis, ichthyosis and deafness (KID)-syndrome. All had characteristic hyperkeratotic skin lesions and neurosensory hearing defects. Two had ophthalmologic symptoms. The third patient did not have eye involvement at the age of 3 years, but exhibited the other typical signs of the syndrome. In none of the three cases were any of the patients' relatives affected, and a spontaneous new mutation is the most likely explanation for the occurrence of this rare syndrome. Histopathological and electron microscopic studies revealed orthohyperkeratosis but no other pathology and no abnormal deposits of glycogen were found. Treatment with the aromatic retinoid etretinate proved to be of little value in any of the patients. The necessity for early audiologic and ophthalmologic evaluation and the need for life-long medical care for patients with KID-syndrome is emphasized.

Congenital melanocytic nevi with halo phenomenon: report of two cases and a review of the literature

Verrucous congenital nevocellular nevi surrounded by a depigmented halo occurring in a 7-year-old boy and a 13-year-old girl were excised and the wounds closed primarily. Histopathologic studies revealed a striking arrangement of the inflammatory infiltrate in these halo nevi. A dense, band-like, lymphohistiocytic infiltrate was found only around and intermingled with A- and B-type nevomelanocytes in the upper dermis, whereas inflammatory infiltrates were completely absent from type C-nevomelanocytes in the lower parts of the reticular dermis. The literature is reviewed with particular consideration of congenital halo nevi.

[The clinical spectrum of mastocytosis]

Mastocytosis comprises a heterogeneous spectrum of clinical manifestations, extending from isolated, benign skin infiltrates to systemic involvement, occasionally with a fatal outcome. After a short survey of the morphology and physiology of the mast cell and the skin lesions of mastocytosis, the involvement of internal organs is reviewed and the differential diagnosis is discussed. The options for therapy are discussed, and the need for continuous monitoring of mastocytosis patients is emphasized.

Intracellular free amino acid patterns in duodenal and colonic mucosa

We report for the first time the concentrations of free amino acids in human intestinal biopsies obtained by routinely performed endoscopy. We studied 15 medical patients with no changes of the mucosa and six HIV-infected persons with duodenitis. The mean (and SD) sum of all amino acids, taurine excepted, was 61.9 (5.4) mmol/kg dry weight in duodenal biopsies of HIV-negative subjects (n = 11) and 82.9 (0.6) mmol/kg in colonic specimens: 50% (44%) of the total (minus taurine) consisted of aspartate and glutamate and 14% (12%), of the essential amino acids. The relative amino acid pattern in duodenum and colon differed completely from that for muscle: aspartate was fourfold higher; glutamate, phenylalanine, glycine, valine, leucine, and isoleucine were about twofold higher. In contrast, glutamine amounted only to 4% (duodenum) to 14% (colon) of muscle glutamine. In duodenal biopsies of the HIV-infected persons, we found significantly (P less than 0.01, except glutamine: P less than 0.025) increased concentrations of glutamate (24.1 vs 17 mmol/kg dry weight), ornithine (1.4 vs 0.4), valine (2.2 vs 1.7), and glutamine.

Intracellular free amino acid patterns in duodenal and colonic mucosa

We report for the first time the concentrations of free amino acids in human intestinal biopsies obtained by routinely performed endoscopy. We studied 15 medical patients with no changes of the mucosa and six HIV-infected persons with duodenitis. The mean (and SD) sum of all amino acids, taurine excepted, was 61.9 (5.4) mmol/kg dry weight in duodenal biopsies of HIV-negative subjects (n = 11) and 82.9 (0.6) mmol/kg in colonic specimens: 50% (44%) of the total (minus taurine) consisted of aspartate and glutamate and 14% (12%), of the essential amino acids. The relative amino acid pattern in duodenum and colon differed completely from that for muscle: aspartate was fourfold higher; glutamate, phenylalanine, glycine, valine, leucine, and isoleucine were about twofold higher. In contrast, glutamine amounted only to 4% (duodenum) to 14% (colon) of muscle glutamine. In duodenal biopsies of the HIV-infected persons, we found significantly (P less than 0.01, except glutamine: P less than 0.025) increased concentrations of glutamate (24.1 vs 17 mmol/kg dry weight), ornithine (1.4 vs 0.4), valine (2.2 vs 1.7), and glutamine.

A low-protein diet protects uremic rats against the negative sequelae of metabolic acidosis

Metabolic acidosis is a common finding in uremia. The metabolic consequences, however, are poorly understood. Thus, the aim of our study was to assess the effect of chronic metabolic acidosis in 5/6-nephrectomized male Sprague-Dawley rats given a normal (18%; n = 19) and a low-protein diet (8%; n = 23). Each of these groups was sequentially given CaCO3 and CaCl2 in the drinking water for a fortnight each. The animals were randomly assigned to start either with CaCO3 or CaCl2 (random cross-over design). The blood pH decreased significantly in both CaCl2 groups (18% protein: CaCO3 7.18 vs. CaCl2 7.11; 8% protein: CaCO3 7.26 vs. CaCl2 7.09) as did standardized base excess (18% protein: CaCO3-5.9 vs. CaCl2-9.7; 8% protein: CaCO3-3.6 vs. CaCl2-12.6). Food intake declined during acidosis in both groups, but more in the 18% protein group. The same occurred with body weight (g) in the 18% group, which decreased dramatically (8% protein: CaCO3 389 vs. CaCl2 390; 18% protein: CaCO3 413 vs. CaCl2 366). The change in body weight was reflected in the urinary urea excretion (mg/24 h/g food) (8% protein: CaCO3 0.9 vs. CaCl2 1.0; 18% protein: CaCO3 2.2 vs. CaCl2 30.8). There was a significant increase in proteinuria (mg/24 h) in the 8% group (CaCO3 10 vs. CaCl2 15), while in the 18% group no real change occurred (CaCO3 24 vs. CaCl2 18). Factoring the proteinuria for food intake, however, also resulted in a tendency towards an increased proteinuria in the 18% group.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple apocrine hidrocystomas on the eyelids

A 31-year-old man with multiple cystic tumors symmetrically distributed on his eyelids is presented. Histopathology and immunohistochemistry suggest the diagnosis of apocrine hidrocystomas. Apocrine hidrocystomas occur frequently on the face, but multiple and symmetrical occurrence on the eyelids has not been reported up to now.

Infusion of dipeptides as nutritional substrates for glutamine, tyrosine, and branched-chain amino acids in patients with acute pancreatitis

In this study we investigated the effect of a total parenteral nutrition supplemented with synthetic dipeptides on plasma and muscle amino acid metabolism in four patients with acute pancreatitis. We infused an amino acid solution containing alanylglutamine, glycylglutamine, glycylvaline, glycylisoleucine, glylcylleucine, and glycyltyrosine for a period of five days in daily dosages of 10.3, 22.1, 68.8, 37.2, 42.5, and 15.7 mmol, respectively. The plasma levels remained below 100 mumol/L for all infused dipeptides. The plasma concentrations of alanylglutamine were not measurable. Mean peptide urine excretion remained below 5%, with the exception of glycylglutamine (8.5% +/- 5.1%). Arteriovenous concentration differences of the dipeptides across the leg were not significantly different from zero, indicating that the infused dipeptides have no important role in the nitrogen exchange of skeletal muscle. A marked intracellular glutamine deficiency in skeletal muscle was found in all four patients (5.1 +/- 0.6 mmol/L v 19.5 +/- 0.8 in healthy subjects) before infusion. Intracellular glutamine concentration was significantly higher after the infusion period (5.1 +/- 0.7 v 9.5 +/- 1.8 mmol/L, P greater than .05), but no normalization of the intracellular glutamine levels was achieved by the infusion of the two glutamine-containing peptides. We conclude that peptides are well metabolized as substrates for parenteral nutrition in catabolic patients. Furthermore, the infusion of glutamine peptides caused a significant increase in intracellular glutamine levels; however, the dosage of glutamine peptides was too low to normalize the muscular glutamine concentrations.

Influence of molecular structure and plasma hydrolysis on the metabolism of glutamine-containing dipeptides in humans

Glutamine-containing dipeptides may serve as a source of glutamine in parenteral nutrition solutions. To study the metabolism of glycyl-L-glutamine (gly-gln) and L-alanyl-L-glutamine (ala-gln) bolus injections of both dipeptides (0.1 mmol/kg within 40 seconds) were performed in five healthy male volunteers. Furthermore, plasma hydrolase activity against both peptides was tested by in vitro incubation. Both peptides were rapidly cleared from plasma after injection; however clearance was significantly greater for ala-gln than for gly-gln (1,595 +/- 124 v 507 +/- 14 mL/min). Arterial concentrations of constituent amino acids rose after peptide injection, indicating hydrolysis of the peptides. Glutamine concentration, for example, rose from 573 +/- 29 to a maximum of 718 +/- 34 mumol/L after gly-gln and from 570 +/- 15 to 900 +/- 53 mumol/L after ala-gln injection. Both peptides were hydrolyzed by plasma hydrolases during in vitro incubation. Hydrolysis was greater for ala-gln than for gly-gln. Half-lives of ala-gln and gly-gln were 46 +/- 3 and 553 +/- 160 minutes, respectively. For both peptides, plasma hydrolysis was too low to contribute significantly to in vivo clearance. Our results indicate that gly-gln and ala-gln are suitable sources for glutamine in parenteral nutrition solutions. Furthermore, plasma hydrolases do not play a significant role in peptide metabolism. Both peptides therefore appear to be primarily metabolized via extracellular hydrolysis, presumably by hydrolases on the cell membranes and consecutive uptake of the liberated amino acid residues.

Metabolism of glutamine in lymphocytes

Pathways of glutamine metabolism in resting and proliferating rat thymocytes and established human T- and B-lymphoblastoid cell lines were evaluated by in vitro incubations of freshly prepared or cultured cells for one to two hours with [U14C]glutamine. Complete recovery of glutamine carbons utilized in products allowed quantification of the pathways of glutamine metabolism under the experimental conditions. Partial oxidation of glutamine via 2-oxoglutarate in a truncated citric acid cycle to CO2 and oxaloacetate, which then was converted to aspartate, accounted for 76% and 69%, respectively, of the glutamine metabolized beyond the stage of glutamate by resting and proliferating thymocytes. Similar results were obtained with the lymphoblastoid T- and B-cell lines. Complete oxidation to CO2 in the citric acid cycle via 2-oxoglutarate dehydrogenase and isocitrate dehydrogenase accounted for only 25% and 7%, respectively. In proliferating cells a substantial amount of glutamine carbons was also recovered in pyruvate, alanine, and especially lactate. The main route of glutamine and glutamate entrance into the citric acid cycle via 2-oxoglutarate in lymphocytes appears to be transamination by aspartate aminotransferase rather than oxidative deamination by glutamate dehydrogenase. In the presence of glucose as a second substrate, glutamine utilization and aspartate formation markedly decreased, but complete oxidation of glutamine carbons to CO2 increased to 37% and 23%, respectively, in resting and proliferating cells. The dipeptide, glycyl-L-glutamine, which is more stable than free glutamine, can substitute for glutamine in thymocyte cultures at higher concentrations.

Calcium-free dialyzate: development and applications

A calcium-free, bicarbonate-containing concentrate was prepared for hemodialysis, which, after dilution, gave analyzed concentrations of sodium of 146 mmol/l, Cl 110 mmol/l, HCO3 of 35 mmol/l and pH of 8.3. When compared with standard bicarbonate dialysis, no important differences in blood chemistries, symptoms or signs were seen. The solution has been trouble-free in over 300 dialyses. Total amount of calcium lost uncorrected for time, dialyzer or blood flow was 40.6 +/- 1.1 mmol, n = 62. This loss was replaced by a calcium infusion into the venous line giving 40 mmol calcium over 4 h. The dialyzate calcium loss could be accurately predicted by sampling without collecting the total dialyzate volume. The uses of this concentrate for bicarbonate dialysis, citrate anticoagulation and avoidance of hypercalcemia in patients treated with oral calcium for phosphate binding is discussed.

[Incorporation of 15N in VLDL and LDL: in vivo synthesis of apolipoprotein B in the post-absorptive and fasting state]

In vivo synthesis of apolipoprotein B 100 (ApoB) was recently determined in man using stable isotopes. With this procedure we analyzed (1) the effect of fasting on synthesis of ApoB from very low density lipoprotein (VLDL) and (2) tracer enrichment in low density lipoprotein (LDL). After a 36-hour fasting period and in the post-absorptive state 4 healthy subjects were given a priming dose (8.7 mumol/kg) of 15N glycine followed by a constant infusion (10 mumol/kg/h for 8 h) to achieve 5% tracer enrichment in the plasma pool of glycine. The K-values, i.e. fractional synthetic rates/hr of ApoB from VLDL were 0.53 +/- 0.26 vs. 0.43 +/- 0.16 (p greater than 0.05). Tracer enrichment in ApoB from LDL at the end of the infusions was 0.19% vs. 1.46% in ApoB from VLDL. The results indicate that (1) in young healthy postabsorptive individuals about 40% of ApoB from VLDL in plasma is synthesized per hour, (2) fasting does not materially affect fractional ApoB synthesis and (3) at 5% 15N enrichment in plasma glycine, tracer enrichment in ApoB from LDL is at the lower limit of detection for the procedure employed.

Nitrogen absorption in pancreatectomized patients: protein versus protein hydrolysate as substrate

To investigate nitrogen absorption in the absence of the pancreas, six patients with total pancreatectomy, all in stable nutritional and metabolic condition, underwent two periods of enteral nutrition identical in all respects except for the nitrogen source. Nitrogen source was either lactalbumin or its hydrolysate. The quantity and quality of calories infused simulated the patient's usual diet, which was a high-protein diet (2.0 +/- 0.4 gm/kg body weight). Pancreatic enzyme replacement therapy was discontinued during each period of enteral nutrition. All patients had greater nitrogen absorption during the enteral nutrition with lactalbumin hydrolysate than that with lactalbumin (91% +/- 2% vs 61% +/- 6% of nitrogen intake, p less than 0.02). Despite this difference in absorption, nitrogen balances during the two periods of enteral nutrition were not significantly different. This appeared to be caused by a urea production rate that was greater during the enteral nutrition with lactalbumin hydrolysate than the rate during that with lactalbumin (26 +/- 1 gm/24 hr vs 16 +/- 3 gm/24 hr, p less than 0.05). Plasma concentrations of amino acids and proteins did not differ significantly during the two treatments. In conclusion, the data suggest that (1) the intestine plays a significant role in protein digestion and that (2) enteral feeding with a protein hydrolysate could eliminate the need for a high-protein diet in patients with pancreatic insufficiency.

[Acrodermatitis chronic atrophicans and sclerodermiform skin changes in Borrelia infection]

A female patient with acrodermatitis chronica atrophicans and widespread sclerodermiform skin lesions with a high IgG antibody titer against Borrelia burgdorferi is presented. The rapid improvement after high-dose penicillin G therapy and the course of the Borrelia antibody titer suggest a persistence of the causative organism.

Influence of two glutamine-containing dipeptides on growth of mammalian cells

The instability of the amino acid glutamine prompted us to investigate substitute compounds appropriate for culture conditions. The effect of two glutamine-containing dipeptides, alanylglutamine (Ala-Gln) and glycylglutamine (Gly-Gln), on the growth behavior of a hematopoietic cell line in culture (K562) was investigated. Growth rates and [3H]thymidine incorporation rates of cells cultivated in sterile-filtrated media, containing glutamine (Gln) or Ala-Gln or Gly-Gln, were not statistically different. Although heart-sterilization of media containing Gln caused approximately 95% decomposition of the Gln, both dipeptides remained unaltered. Consequently, cell growth was drastically decreased when autoclaved free Gln-containing media were used, but growth was unaffected in the presence of autoclaved dipeptides. Both Ala-Gln and Gly-Gln have an advantage over free Gln as growth factors for cell culture due to the stability of the dipeptides during both autoclaving and storage; the biological activity, however, is comparable.

Substitution therapy of hypogonadal men with transdermal testosterone over one year

Current testosterone substitution therapy either by injectable or oral testosterone esters suffers from markedly fluctuating serum testosterone levels often far above or below the physiological range. Recently, a transdermal therapeutic system (TTS) for the delivery of testosterone was developed which, when applied to the scrotum, provides smooth serum testosterone levels. Here we report results from seven hypogonadal men treated with the TTS for 14 months by applying a new patch every day. In all patients serum testosterone and dihydrotestosterone (DHT) determined 3-5 h after applying a new patch increased significantly and remained within the physiological range during the entire treatment period. The DHT/testosterone ratio remained constant. In 4 of these patients and 2 others under TTS treatment serum testosterone and DHT were also determined over a 24-h period at regular intervals. In these patients serum testosterone levels in the physiological range were seen during the entire observation period, whereas an increase in the DHT/testosterone ratio occurred towards the end of the one-day treatment phase. All patients in the 14-month treatment study were clinically well substituted and responded with good compliance. Clinical chemistry showed no abnormalities during treatment. Thus, the TTS appears to be an effective and safe new modality for the treatment of male hypogonadism.