Suitability of the Vero cell method for titration of diphtheria antitoxin in the United States potency test for diphtheria toxoid

The in vitro Vero cell method for titration of diphtheria antitoxin in immunized guinea pig sera was standardized to obtain comparable results to the in vivo toxin neutralization (TN) test in guinea pigs used to test potency of adsorbed diphtheria toxoid according to the United States Minimum Requirements. In the Vero cell method, the antitoxin titers of the guinea pig sera, obtained 4 weeks after immunization, were markedly dependent on the toxin dose level used in the assay. A toxin dose level termed the Lcd/1 dose (limit of cytopathic dose at 1 IU/ml) for Vero cell method gave comparable estimates of antitoxin activity to the in vivo TN method performed at L+/1 dose of toxin. The Lcd/1 toxin dose level for the Vero cell method is defined as the minimum concentration of diphtheria toxin required to produce a cytopathic effect on Vero cells in 4 days when the solution of diphtheria toxin is mixed with an equal volume of standard diphtheria antitoxin whose concentration is 1 IU/ml. When lower dose levels of toxin were used in the Vero cell assay (Lcd/10 to Lcd/1000), the concentrations of antitoxin in 4 weeks guinea pig sera were 2 to 11.7 times lower than with the Lcd/1 dose level and similarly lower than those measured by the in vivo TN test at L+/1 level. In contrast, the concentration of antitoxin measured in sera from guinea pigs who have been boosted with diphtheria toxoid increased approximately two-fold with the Lcd/1000 dose level.(ABSTRACT TRUNCATED AT 250 WORDS)

Muscular sufficiency, serum protein, enzymes and bioenergetic studies (31-phosphorus magnetic resonance spectroscopy) in chronic malnutrition

Muscle sufficiency was significantly lower in 1336 children with chronic malnutrition of moderate to severe degree. Eighteen children with a chronic moderate degree of malnutrition and 8 well-nourished, age-matched controls were selected for biochemical and 31-phosphorus magnetic resonance spectroscopy (31-P MRS) studies. The results showed that: (a) serum total protein, albumin, iron, calcium and inorganic phosphate were similar in both groups; (b) serum enzyme levels were significantly increased in the malnourished group; (c) 31-P MRS showed significantly higher means for total ATP, beta-ATP, alpha-ATP and inorganic phosphate for the malnourished compared to the control group. In chronic malnutrition, proteins are maintained by degradation in muscle resulting in release of amino acids and enzymes. 31-P MRS studies showing increases in total ATP, beta-ATP and inorganic phosphate and a decrease in phosphocreatine suggest that ATP is maintained at the cost of phosphocreatine.

Comparison of adjuvant activities of aluminium phosphate, calcium phosphate and stearyl tyrosine for tetanus toxoid

The adjuvant activity of three adjuvants, aluminium phosphate (AIPO4), calcium phosphate (CaHPO4) and stearyl tyrosine for tetanus toxoid (TT) were compared to soluble TT in mice at a dose of 0.5 Lf (1/10th of the single human dose) and in guinea-pigs at a dose of 7.5 Lf (1.5 times the single human dose). Three TT preparations varying in purity were used: (1) ammonium sulphate precipitated formalin detoxified tetanus toxin (AS-TT); (2) AS-TT ultrafiltered to remove low molecular weight peptides (UF-TT): and (3) chromatographically purified tetanus toxin subsequently detoxified with formalin (CP-TT). After primary immunization of mice, AIPO4 absorbed TTs induced higher toxin-neutralizing and IgG (by ELISA) antibodies than CaHPO4, stearyl tyrosine adsorbed or soluble TT preparations, but this difference was no longer present after secondary immunization. TT preparations of varying purities showed similar antibody responses after primary and secondary immunizations when adsorbed on each adjuvant. CP-TT preparation showed the highest neutralizing antibody level amongst soluble preparations after the first dose. All the preparations induced mainly IgG1 antibodies. However, stearyl tyrosine adsorbed TT induced relatively higher IgG2a and IgG2b responses than AIPO4, CaHPO4 adsorbed or soluble TTs particularly after booster injection. No preparation induced detectable IgG3 or IgM antibodies. AIPO4 adsorbed preparations induced higher IgE antibodies than CaHPO4 and stearyl tyrosine adsorbed vaccines. Among the soluble preparations, CP-TT induced lower anti-TT IgE antibodies than standard AS-TT. All these preparations were also tested in the US potency test for adsorbed TT in guinea-pigs. While all the preparations passed this test, AIPO4 adsorbed TT preparations induced higher neutralizing and IgG antibodies than CaHPO4 and stearyl tyrosine adsorbed or soluble TT preparations. In these animal models, purified TT was a strong immunogen and traditional AIPO4 adjuvant gave the highest antibody responses.

The role of early flap coverage in the management of open fractures of both bones of the leg

Sixty patients with type III injuries (open fractures) of the tibia were treated in a prospective fashion by combined orthopaedic and plastic surgical schemes based on the principles of early radical cleaning, a second-look operation, and early coverage of soft tissue defects with an appropriate local or distant flap. Stabilization of fractures was achieved by external fixation in most cases and patients were allowed to walk within 4-8 weeks (partial weight bearing). Bony union was achieved in 23.4 weeks. The mean hospital stay was 3.5 weeks. Limb salvage was achieved in all cases and there were no major complications.

Diagnosis of umbilical metastasis (Sister Mary Joseph's nodule) by fine-needle aspiration: an immunocytochemical study

During a ten year period, since we introduced needle aspiration cytology at our institution, we have diagnosed five cases of umbilical metastasis (Sister Mary Joseph's nodule). In none of the cases was any false negative or false positive diagnosis rendered and the primary carcinoma was found below the diaphragm. In all the five cases, cell blocks of the aspirate were subsequently prepared, and highlighted the histologic features of the tumour which corresponded with the cytologic diagnosis. Immunohistochemical staining on the aspirate material in all the cases was considered quite useful in substantiating the cytohistologic diagnosis. Based on our findings, we suggest that fine-needle aspiration cytology as an initial diagnostic procedure in cases suspected of umbilical metastasis should be considered, since it is not only a simple, fast, accurate, and inexpensive diagnostic procedure, but can also save the patient from an invasive surgical procedure, the benefit of which is questionable.

Studies on the inheritance of repellent tolerances in Aedes aegypti

Two laboratory strains and 6 inbred strains of Aedes aegypti were tested against deet, ethyl hexanediol, dimethyl phthalate, and Indalone. Reciprocal crosses and backcrosses of 2 inbred strains were tested against deet only. Results obtained were compatible with a quantitative genetic model in which the effects of the factors involved were multiplicative. Certain inbred strains differed significantly from cognate laboratory and/or inbred strains in tolerance to one or more test materials. Heritability in the broad sense (H2) was estimated at 0.05 for deet, 0.22 for ethyl hexanediol, 0.48 for dimethyl phthalate, and 0.51 for Indalone. Partial dominance was observed in the inheritance of tolerance to deet.

Impact of television on children

Television viewing has a great impact on various aspects of child's life. This study was carried out at Sir Padampat Mother & Child Health Institute, Jaipur (Rajasthan). The aim was to study the effects of television viewing on a child's eating habits, general physical health, physical activities, interest in study and school performance. Only 250 children of 3-10 years age groups were studied for a period of nine months (January 1992 to September 1992). Average duration of television exposure to an individual child was 18.5 hours per week in the study. Significant changes were observed in a childs' eating habits, weight, physical activity, sleep pattern, interest in study and general physical health. Increase in weight was observed in 19.6% children suggesting that the television viewing may predispose to childhood obesity. In 30.4% cases decrease in physical activity was found, 18.4% children showed decreased interest in study, while 10% children showed decrease in school performance, and sleep pattern was disturbed in 24% children. Medical problems were found in 11.6% children. Significantly two children had precipitation of fits on television viewing.

Biodegradable microspheres as controlled-release tetanus toxoid delivery systems

Purified tetanus toxoid, a high-molecular-weight protein, was entrapped within poly(L-lactic acid) (PLA) and poly(D,L-lactic/glycolic acid) (PLGA) microspheres prepared by either a solvent extraction or a solvent evaporation method carried out in a multiple emulsion system (water-in-oil-in-water). The physical integrity and antigenicity of the protein treated under different processing conditions were investigated. A reduction of antigenicity that was related to the percentage of aggregated protein was noticed under some experimental conditions. This partial loss of antigenicity was associated with the lyophilization process and affected by the nature of the organic solvent. All types of microspheres prepared with different molecular weight PLA and PLGA displayed a high protein-loading efficiency (> 80%) but their size was strongly influenced by polymer molecular weight (3000 versus 100,000). Protein release pattern was influenced by both polymer molecular weight and composition (PLA versus PLGA). A constant release pattern after an induction period of 10 days was observed for microspheres composed of high-molecular-weight polymers (PLA and PLGA). The release rate was lower from PLA microspheres than from PLGA microspheres. In contrast, a continuously increasing release rate preceded by a burst was observed for low-molecular-weight (3000) PLGA microspheres. Microencapsulated tetanus toxoid was significantly more immunogenic in mice than fluid toxoid as determined by IgG anti-tetanus antibody levels and neutralizing antibodies. However, the magnitude and duration of the antibody response did not differ significantly from a similar dose of aluminium phosphate-adsorbed toxoid. We conclude that microencapsulated tetanus toxoid shows significant adjuvant activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Tuberculous radiculomyelitis (arachnoiditis): myelographic (and CT myelographic) appearances

Tuberculous radiculomyelitis (arachnoiditis) remains one of the important causes of paraplegia in India. The diagnosis usually rests on clinical history and examination, and on laboratory findings in the cerebro-spinal fluid (CSF). Few descriptive reports are available of the myelographic appearance, with water-soluble contrast media, in tuberculous radioculomyelitis (arachnoiditis). A retrospective review of 21 myelograms and 10 computed tomographic (CT) myelograms, in 14 patients with tuberculous radiculomyelitis, was carried out, with a view to describing, in detail, the radiographic features. An attempt was made to assess the use of the radiologic procedures in diagnosis and follow up in these patients. Conventional myelographic findings included block (8/14), irregular subarachnoid space (9/14), filling defects (8/14), sluggish contrast flow (2/14), root thickening (3/14) and atrophic cord (2/14). Computed tomographic myelography showed reduced contrast density in portions of the opacified CSF ring around the cord in affected region (6/7) and, in addition, demonstrated septa and adhesions. Intravenous contrast CT was not found to be useful (2/2). Follow-up studies showed partial resolution (3/6), deterioration (1/6) and status quo of radiological findings (2/6). Although these changes can be seen in chronic radiculomyelitis (arachnoiditis) from other causes, such as leukaemic infiltration/lymphoma, other chronic central nervous system infections and iatrogenic causes, including repeated intrathecal injections, conventional myelography appeared to be useful for diagnosis and follow up in tuberculous radiculomyelitis (arachnoiditis).

MR imaging and angiography in tuberculous meningitis

MRI was performed on 26 patients with tuberculous meningitis, with particular reference to document the cranial nerve abnormalities. MR angiography (MRA) was performed in 20 of the patients. Meningeal enhancement in the basal cisterns or over the convexity of brain was seen in all patients; two show ependymal enhancement. Tuberculomas, single (3), multiple (12) or miliary (2) were detected in 17 patients. Of the 9 patients with cranial nerve palsies, 7 showed contrast enhancement with or without thickening of the involved nerve. Abnormality signal intensity of the involved nerve was seen on proton density and T2-weighted images in one of these patients. MRA revealed focal arterial narrowing in 10 patients, the vessels commonly affected being the terminal segment of the internal carotid artery and the proximal segments of the middle and anterior cerebral arteries. One patient also had a small aneurysm of the proximal middle cerebral artery. Infarcts, haemorrhagic (8) or bland (6), were detected in 14 patients; most were the basal ganglia and internal capsules, large middle or anterior cerebral arterial territory infarcts being seen in only two cases.

Is the higher incidence of ischemic disease in patients with hypertension and diabetes related to intracellular depletion of high energy metabolites?

To study mechanisms underlying ischemia in hypertension and non-insulin dependent diabetes mellitus (NIDDM), 31P-magnetic resonance spectroscopy was used to evaluate adenosine triphosphate and 2,3 diphosphoglycerate (2,3 DPG) levels in erythrocytes of control (n = 21), hypertensive (n = 22), and NIDDM (n = 10) subjects. Compared to adenosine triphosphate levels in controls (2.22 +/- 0.10 mM), both hypertensive (1.89 +/- 0.10 mM, sig = 0.05 versus normal) and NIDDM subjects (1.57 +/- 0.13 mM, sig = 0.05 versus normal) exhibited lower values. NIDDM subjects also displayed suppressed levels of 2,3 DPG (6.84 +/- 0.48 mM, sig = 0.05 versus normal and EH), compared to hypertensives (8.34 +/- 0.27 mM). These data suggest cellular energy metabolism is disrupted in hypertension and NIDDM. Both conditions may thereby sensitize tissues to ischemic damage, lower adenosine triphosphate levels by decreasing energy reserves, and lower 2,3 DPG levels by inhibiting hemoglobin-oxygen dissociation.

MRI in intraspinal tuberculosis

We studied 20 patients with intraspinal tuberculosis (TB), to characterise the MRI features of tuberculous meningitis and myelitis. MRI leptomeningitis and intramedullary involvement in 11 patients, intramedullary lesions alone in 5, leptomeningitis alone in 2, and isolated extradural disease in 2. TB leptomeningitis was characterised by loculation of the cerebrospinal fluid (CSF), nerve root thickening and clumping (seen only in the lumbar region) or complete obliteration of the subarachnoid space on unenhanced images. Gd-DTPA-enhanced images proved useful in 6 cases, revealing linear enhancement of the surface of the spinal cord and nerve roots or plaque-like enhancement of the dura-arachnoid mater complex. Intramedullary lesions included tuberculomas (8), cord oedema (5) and cavitation (3). In seven cases of intramedullary tuberculoma multiple lesions with skip areas were seen, without significant cord swelling. One patient had an isolated lesion in the conus medullaris. The lesions were iso- or hypointense on T1-weighted images, iso-, hypo- or hyperintense on T2-weighted images and showed rim or nodular enhancement with contrast medium.

Linking radiosilver to monoclonal antibodies reduced by ascorbic acid. Comparison of results with stable silver using gravimetric technique and silver 110-M using radiotracer technique

Radiosilver-111 and Radiogold-199 were proposed by us (1) as suitable isotopes for radioimmunotherapy in areas such as India by reason of their suitable half-lives and B-emissions (Ag-111 T1/2 = 7.45 d and Au-199 T1/2 = 3.15 d). Since silver is monovalent, it is difficult to link to conventional bifunctional chelates. We therefore explored the use of sulfur-based linkers (2). Encouraged by the Thakur and De Fulvio Technique (3) of linking technetium to disulfide groups in antibodies reduced by ascorbic acid that is eminently biocompatible, we have explored the linkage of silver to immunoglobulin reduced by ascorbic acid. The linkage of silver was assessed with stable Ag-108 using dialysis to quantify the free silver after the reaction of silver and reduced immunoglobulins in various molar ratios (1:1, 1:2, 1:5, 1:10). The silver quantity was estimated gravimetrically after precipitation as chloride. It was observed that using these molar ratios there was negligible silver efflux into the dialysate, suggesting stable linkage. We also assessed the linkage using Ag-110M as radiotracer. The comparative results with the two techniques are described.

Proliferation of Reed-Sternberg cells and variants in Hodgkin's disease

The proliferative activity and the origin of multinucleated Reed-Sternberg cells and mononuclear variants in Hodgkin's disease have been studied in the past using several techniques. The presence of both proliferating-cell nuclear antigen and the cell-proliferation-associated antigen Ki-67 have also been reported in Hodgkin's disease. P34cdc2 is the protein product of the cell-cycle-control cdc-2 gene. Using a monoclonal antibody against the protein p34, cases of three different histological subtypes of Hodgkin's disease have been studied along with normal tonsil and follicular lymphoma as controls. In all these cases of Hodgkin's disease, positive p34 staining was seen in the majority of Reed-Sternberg cells and mononuclear variants (> 80%), along with a proportion of small lymphocytes, mainly T cells. Staining was predominantly cytoplasmic and occasionally additional nuclear signals were apparent. In two cases, double immunostaining with the anti-p34 antibody and CM-1 for p53 demonstrated positive signals for both proteins within the same neoplastic cells. Although the presence of p34 in Reed-Sternberg or variant cells reflects mitosis and hence suggests proliferation, the possibility of endomitosis remains and may explain the multinucleated appearance of Reed-Sternberg cells.

Role of repellents in vector control and disease prevention

Repellents are an inexpensive and practical means of protection against nuisance and disease vector arthropods in conjunction with or when other control measures are not feasible. Appropriate selection of skin and/or clothing repellents along with proper wear of clothing can provide adequate protection from biting arthropods, and are available in a wide variety of forms including lotions, creams, foams, soaps, aerosols, sticks, and towellettes. A coordinated effort among different research groups associated with advances in the science of insect repellents such as mode of action information, doses of repellents to generate threshold level responses and controlled release delivery mechanisms, may help in understanding the mechanisms by which repellents work. This in turn may revolutionize the development of repellents for personal protection and their use in vector control.

Removal of endotoxin from antibody preparations for clinical use. Assessment of polymyxin-sepharose CNBr affinity chromatography

Despite attempts to maintain asepsis, good manufacturing practices, and the use of terminal sterilization by millipore filtration, the nuclear practitioner is always worried about the possibility of endotoxin contamination. Methods, such as ion-exchange chromatography, have been tried for removing endotoxins during the preparation of radiolabeled antibodies, and so on. As suggested by Stevenson (1990), we evaluated the Issekutz technique (1) of endotoxin removal by affinity chromatography using a polymyxin cyanogen bromide (CNBr) Sepharose column. The endotoxin content of millipore filtrates of heat killed/sonicated suspensions of Pseudomonas pyocyaneus, E. coli were measured using a Sigma (St. Louis, MO) Endotoxin Assay Kit before and after filtration through such columns and compared with the results obtained using gel exclusion and ion-exchange columns of the same length and diameter. Reduction of endotoxin content to undetectable levels by the polymyxin column was observed. The use of such columns for terminal endotoxin removal analogous to terminal sterilization is advocated especially when developing a radiopharmaceutical such as radiolabeled antibodies for in house use.

Signal intensity patterns in intraspinal dermoids and epidermoids on MR imaging

Retrospective evaluation of MR images of nine intraspinal dermoid (n = 4) and epidermoid (n = 5) tumours was undertaken. T1-weighted images were available in all the patients while proton density (PD) and T2-weighted images were available in seven patients. Except for one lesion (only T1-weighted images were available in this case), all the lesions were clearly delineated on MR images. Most (5 out of 7) were better appreciated on T1- and PD-weighted images than on T2-weighted images. On T1-weighted images, the epidermoids were either iso- to mildly hypointense to the cord (n = 3), isointense to CSF (n = 1) or markedly hyperintense (n = 1). On the PD images, the epidermoids were either isointense to cord (n = 3) or markedly hyperintense (n = 1). All the lesions were iso- to hyperintense to CSF on T2-weighted images. Of the four dermoids three showed a mixed intensity pattern on all sequences; the dominant component gave short T1 and short T2 values, consistent with fat. The fourth lesion showed homogenous material with a signal intensity intermediate between that of CSF and cord on T1-weighted images. Dermal sinus tracts were present in four of the nine patients; three patients had an intraspinal component. This study shows that although MR imaging is excellent for their detection, it cannot differentiate the two tumour types.

19F nuclear magnetic resonance studies of free calcium in heart cells

19F nuclear magnetic resonance is used in conjunction with 5,5'-difluoro-1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (5FBapta), a fluorinated calcium chelator, to report steady-state intracellular free calcium levels ([Ca2+]i) in populations of resting, quiescent, isolated adult heart cells. 31P nuclear magnetic resonance shows that 5FBapta-loaded cells maintain normal intracellular high-energy phosphates, pH, and free Mg2+. The intracellular free calcium concentration of well perfused, isolated heart cells is 61 +/- 5 nM, measured with 5FBapta, which has a dissociation constant (Kd) for calcium chelation of 500 nM. A similar value is obtained with Quin-MF, another fluorinated calcium chelator with Kd and maximum calcium sensitivity at 80 nM. We find that the steady-state level of intracellular free calcium is increased by decreased extra-cellular sodium concentration, omission of extracellular magnesium, decreased extracellular pH, hyperglycemia, and upon treatment with lead acetate. Further, extracellular ATP caused a large transient increase in [Ca2+]i. Thus, while heart cells maintain a very low level of intracellular free Ca2+, acute alterations in extracellular environment can cause derangement of calcium homeostasis, resulting in measurable increases in [Ca2+]i.

Adrenal tumor complicating untreated 21-hydroxylase deficiency in a 5 1/2-year-old boy

OBJECTIVE

A 5 1/2-year-old boy presenting with virilization was diagnosed as having classic 21-hydroxylase deficiency complicated by an adrenal tumor. We attempted to document a reduction in the size of the tumor with glucocorticoid therapy.

DESIGN

Case study.

SETTING

Referral center.

INTERVENTION

Glucocorticoid therapy was instituted for congenital adrenal hyperplasia. Surgery for the adrenal mass was deferred, and the size of the mass was monitored by serial ultrasonography.

RESULTS

Baseline values of serum 17 alpha-hydroxyprogesterone (186.6 nmol/L) and testosterone (24.7 nmol/L [7.1 ng/mL]) were elevated. After instituting steroid treatment, 17 alpha-hydroxyprogesterone was suppressed (13.0 nmol/L), and testosterone remained undetectable on follow-up. However, the size of the mass increased during 6 months. Unilateral adrenalectomy performed at that time revealed a well-encapsulated adenoma in a hyperplastic gland.

CONCLUSIONS

Untreated classic congenital adrenal hyperplasia may be complicated by an adrenal tumor even at a young age. Suppression of adrenal androgens by glucocorticoid therapy was not accompanied by regression of the tumor in our patient.

Cytodiagnosis of pseudomyxoma peritonei in cases suspected of ovarian tumours

The cytologic features in four cases of pseudomyxoma peritonei are described in ascitic fluid specimens which were received from female patients suspected of ovarian masses. The findings in the fluid included cells of mesothelial origin and spindle-shaped fibroblasts with a significant amount of background mucin. This was confirmed by mucicarmine and Alcian blue stains. A cytologic diagnosis of pseudomyxoma peritonei was possible in all four cases. The above findings were further substantiated since mucinous ovarian neoplasms were found in all the cases.

31P-NMR study of transient ischemia in rat hippocampal slices in vitro

Intracellular high energy phosphates (HEP) were monitored in rat hippocampal slices in vitro by 31P-NMR during continuous superfusion, no flow and reperfusion in order to model the changes which occur during cerebral ischemia and reperfusion in vivo. With continuous superfusion, stable intracellular HEP resonance signals were observed for over 4 h. When superfusion was stopped, there were rapid decreases in pH and phosphocreatine levels followed by slower loss of ATP. These changes are similar to those observed during cerebral ischemia in vivo by 31P-NMR. Upon reperfusion, the pH returned to normal, but the extent of HEP recovery depended on the length of time superfusion was halted. Following a 10 min ischemic period HEP levels returned to greater than 90% of preischemic values, while following a 16 min ischemic period there was only 60% recovery. Superfusion with low calcium, high magnesium medium significantly improved the recovery of HEP following 16 min of ischemia to 80% of preischemic levels. These data support the hypothesis that calcium influx during and following ischemia can disrupt energy metabolism in the hippocampus, and that magnesium can have a protective action on cellular energy status, perhaps by further blocking calcium influx.

Epstein-Barr virus infection and bcl-2 proto-oncogene expression. Separate events in the pathogenesis of Hodgkin's disease?

The present study was undertaken to investigate whether Epstein-Barr virus-(EBV) encoded latent membrane protein (LMP) induces the expression of BCL-2 in Hodgkin and Reed-Sternberg (HRS) cells of Hodgkin's disease (HD) and thereby provide a possible mechanism for the role of EBV in the pathogenesis of this disease. Fifty-three cases of HD were studied for the presence of EBV using EBV-encoded RNA in situ hybridization and LMP immunohistochemistry. Immunostaining for BCL-2 on paraffin material was performed using microwave treatment of tissue sections before the application of the primary monoclonal antibody. EBV was located in HRS cells in 16 cases (30%). All cases that were EBV-encoded RNA in situ hybridization positive, also expressed LMP. BCL-2 expression in HRS cells was detected in 16 cases (30%), but only two of these were also EBV-positive. In both of these cases, only occasional HRS cells expressed BCL-2, in contrast to LMP, which was detected in nearly all such cells. BCL-2 staining was predominantly cytoplasmic with some membrane pattern. These results demonstrate that BCL-2 expression can be detected in HRS cells in routinely processed HD tissue and that whereas EBV does not induce the expression of BCL-2 in HD, BCL-2 may have a role in the pathogenesis of EBV-negative cases of HD.

Effect of ASTA-Z 7575 (INN Maphosphamide) on human lymphokine-activated killer cell induction

Recent studies combining chemotherapeutic agents with various biological response modifiers for the treatment of cancer have shown promising results. Cyclophosphamide (Cy) is the most widely used alkylating agent and a major constituent of combination chemotherapy regimens for many neoplastic diseases. It has been reported that Cy is a cytotoxic drug, which becomes immunosuppressive at higher doses. A synthetic metabolite of Cy, ASTA-Z, has recently been produced. ASTA-Z is more active and stable by itself and does not need to be metabolically converted to an active compound. The combined effect of Cy and interleukin-2 (IL-2) on the induction of lymphokine-activated killer (LAK) cells is not known. Therefore, we decided to investigate the effect of ASTA-Z on the induction and function of LAK. The coculture of peripheral blood mononuclear cells (PBMC) with various concentrations of ASTA-Z (0, 10(-6), 10(-5), 10(-4), and 10(-3) dilution) and IL-2 (50 U/ml) for 4 days produced significant suppression of cytotoxicity and lytic ability of the LAK cells against NK-sensitive (K562) and NK-resistant (M14) tumor cell lines. The lower doses of ASTA-Z did not affect the generation of LAK cells, its cytotoxicity and lytic ability of ASTA-Z against both NK-sensitive and NK-resistant tumor cell lines. Furthermore, the ASTA-Z produced dose-dependent suppression of the proliferative response of LAK cells. The significant therapeutic benefit in the cancer patient may be achieved by the low dose regimen of Cy and IL-2 because it has no deleterious effect on the induction and function of LAK cells.

Low extracellular magnesium induces intracellular free Mg deficits, ischemia, depletion of high-energy phosphates and cardiac failure in intact working rat hearts: a 31P-NMR study

Hemodynamic and 31P-NMR spectroscopic studies were performed on intact, perfused working rat hearts exposed to low (0.3 mM) extracellular Mg([Mg2+]o). Low [Mg2+]o perfusion resulted in rapid and significant falls in cardiac output, coronary flow, stroke volume, developed pressure and the rate-pressure product. Concomitant with this O2 consumption decreased and lactate production increased. Hearts perfused with 0.3 mM, instead of 1.2 mM, [Mg2+]o exhibited significant reductions in [ATP], [PCr], intracellular free Mg ([Mg2+]i), and pHi; a marked rise in intracellular Pi corresponding to a precipitous fall in the cytosolic phosphorylation potential was seen. Reintroduction of 1.2 mM [Mg2+]o failed to reestablish either normal hemodynamics, or high-energy phosphates and intracellular Pi, suggesting irreversible myocyte injury. These observations are consistent with the tenet that low [Mg2+]o can result in marked reduction in oxygen and substrate delivery to the cardiac myocytes, probably as a result of coronary vasoconstriction.