Effects of protein kinase inhibitors on the stimulated neutrophil responses by degraded immunoglobulin G

Effects of protein kinase C inhibitors, staurosporine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine dihydrochloride and protein tyrosine kinase inhibitors, genistein, tyrphostin and 2,5-dimethylcinnamate on the neutrophil responses stimulated by immunoglobulin G (IgG), complement C5a or platelet-activating factor were studied. After receptor binding, the role of protein kinase C and protein tyrosine kinase in the stimulation of neutrophil responses, superoxide production and lysosomal enzyme release in degraded IgG-activated neutrophils may be similar to chemoattractant-stimulated cells. In contrast to complement C5a or platelet-activating factor, protein tyrosine kinase appears to play an important role in the regulation of intracellular Ca2+ mobilization in neutrophils activated by degraded IgG rather than by protein kinase C.

Pharmacokinetic interaction between intravenous 2',3'-dideoxyinosine and pentamidine in rats

PURPOSE

This study examined the pharmacokinetic interaction between 2',3'-dideoxyinosine (ddI) and pentamidine.

BACKGROUND

ddI and pentamidine are often coadministered to patients with acquired immunodeficiency syndrome, and are both associated with pancreatic toxicity. Information on potential interaction would be useful to assess the need for dose modification and the basis of the higher incidence of pancreatic toxicity associated with coadministration of the two drugs.

METHODS

ddI (200 mg/kg) and pentamidine (10 mg/kg) were administered by continuous infusion to rats over 3 hr, either alone or concomitantly. Drug analysis was by high pressure liquid chromatography with UV or fluorescence detection, or by radioimmunoassay.

RESULTS

Pentamidine coadministration significantly increased the apparent volume of distribution at steady state of ddI from 1.4 to 3.4 l/kg (p = 0.004), and increased the mean residence time from 36.3 to 50.0 min (p = 0.015). Pentamidine enhanced the distribution of ddI from plasma into pancreas (p = 0.001) and muscle (p = 0.026). ddI distribution into spleen and liver was also increased, with differences approaching statistical significance (p = 0.08 and 0.06, respectively). In contrast, ddI coadministration did not affect the total body clearance but increased the urinary excretion and the renal clearance of pentamidine by about 5-fold (p = 0.0003).

CONCLUSIONS

These data indicate that pentamidine increased the distribution of ddI into pancreas and muscle, whereas ddI increased the renal elimination of pentamidine.

WR-1065 and radioprotection of vascular endothelial cells. I. Cell proliferation, DNA synthesis and damage

Normal tissue toxicity limits radiation therapy and could depend on the extent of damage to the vascular endothelium Aminothiols such as WR-1065 [N-(2-mercaptoethyl)-1,3-diaminopropane] provide radioprotection for normal tissues, but little is known about how the aminothiols specifically affect the endothelium. Bovine aortic endothelial cells in culture were exposed to WR-1065 for 2 h before irradiation (137Cs gamma rays, 1 Gy/min). Alone, WR-1065 demonstrated an antiproliferative effect that was related to dose (0.5-4 mM) and was evident by lowered counts of adherent cells 48 h after exposure. WR-1065 was clearly radioprotective when assessed by colony formation and incorporation of [3H]thymidine. However, when the number of adherent cells was evaluated, radioprotection appeared to be slight and evident only in logarithmically growing cells. WR-1065 at 2 mM suppressed single-strand DNA breaks after 3 Gy by 22% and double-strand breaks after 9 Gy by 47%. Also in the irradiated cells, WR-1065 more than doubled the rate of progression of cells from G1 to S phase. WR-1065 pretreatment elevated cellular glutathione (GSH) content more than twofold. Although pretreatment with buthionine sulfoximine inhibited the elevation of GSH, the radioprotective impact of WR-1065 on total DNA strand breaks and colony formation was unaffected. These results suggest that WR-1065 may enable tissue recovery from irradiation by promoting the replication of endothelial cells, possibly by mechanisms independent of GSH.

Neurotrophin-induced modulation of synaptic transmission in the adult hippocampus

The NGF-family of neurotrophic factors including NGF, BDNF and NT-3,4/5 is known to be crucial for neuronal survival and differentiation during development. However, recent studies suggest that the neurotrophins are also widely expressed and play a dynamic role in the mature nervous system. One of the major sites of expression of the neurotrophins in the adult brain is the hippocampus which has been also popular as an important structure for the adult plasticity. Moreover, the level of expression of the neurotrophins in the hippocampus can be regulated by a variety of neuronal inputs, such as experimentally-induced seizures, injection of glutamate receptor agonists, and LTP-inducing stimulation. The possibility that the neurotrophins modulate synaptic transmission in the mature brain has been investigated at the Schaffer collateral-CA1 synapses in the adult rat hippocampus. We report that transient application of BDNF and NT-3, but not NGF induces a long-lasting increase of synaptic transmission, which is likely to be mediated by Trk family of receptor tyrosine kinases. Both BDNF and NT-3 decrease paired pulse facilitation, suggesting a possible presynaptic modification. Interestingly, previous potentiation of synaptic activity by the application of neurotrophic factors does not occlude the induction of long-term potentiation. These results suggest that the neurotrophins may locally regulate synaptic plasticity in the adult nervous system.

Tissue pharmacokinetics of 2',3'-dideoxyinosine in rats

The present study examined in rats the concentration-time profiles of 2',3'-dideoxyinosine (ddI) in pharmacologically relevant tissues, including organs where drug effects are desired (brain, lymph nodes, spleen), organs with known drug toxicity (pancreas), and major eliminating organs (liver, kidney). ddI was analyzed by high performance liquid chromatography and radioimmunoassay. In the liver, pancreas, spleen, brain and lymph nodes, the highest concentrations were reached between 4 and 7 min after drug administration. The concentrations subsequently declined in parallel with those in plasma, indicating that plasma and these tissues were in rapid equilibrium. The concentrations in these tissues were less or equal to that of plasma. In the kidney, the maximal concentration occurred at a later time of 14 min, after which concentrations also declined in parallel to those in plasma. The kidney concentrations were about 10-fold greater than plasma concentrations. The ratios of tissue-to-plasma concentrations and of areas under the tissue and plasma concentration-time profiles showed a 230- to 300-fold range with the rank order of kidney >> liver approximately pancreas > lymph nodes > spleen >> brain, with respective values of 10.4, 1.09, 0.90, 0.75, 0.42, and 0.04. These data indicate no accumulation of ddI in brain, lymph nodes, spleen, pancreas and liver, and a significant accumulation in the kidney. The low tissue-to-plasma ratios in brain and spleen and a moderate ratio in lymph nodes indicate that further enhancement of the therapeutic effect of ddI requires improved drug delivery and entrapment in these tissues.

Characterization of beta-glucosidase and beta-glucuronidase of alkalotolerant intestinal bacteria

The number of alkalotolerant intestinal bacteria was 1% of the total flora in humans and 0.8% of those in rats. The beta-glucosidase and beta-glucuronidase activity of these intestinal bacteria was induced by elevating the pH of the medium, but the growth was not changed. The enzyme activity in a medium of pH 7 was 5- to 10-fold higher than that in a medium of pH 6. Isolated bacteria from human and rat feces were cultured in a pH 5 general anaerobic medium (GAM) broth to reach a stationary phase, then the pH of the media was changed from 5 to 8. Both beta-glucosidase and beta-glucuronidase were increased 9.2-12.1-fold. The activity of these enzymes was also increased 2-16-fold by adding substrates (p-nitrophenyl-beta-D-glucuropyranoside or p-nitrophenyl-beta-D-glucuronide). beta-Glucuronidase(s) was inhibited by saccharic acid 1,4-lactone or D-glucuronic acid. However, when lactulose was added to the medium, and then intestinal microflora were inoculated in the medium, the productivity of these enzymes dramatically decreased. We thus contend that the induction of the beta-glucosidase and beta-glucuronidase of intestinal bacteria by a high pH can cause colorectal cancer.

Natural occurrence of Fusarium mycotoxins (trichothecenes and zearalenone) in barley and corn in Korea

Barley is produced in four provinces, Chonbuk, Chonnam, Kyungbuk, and Kyungnam, and corn is mainly produced in the Kangwon province in Korea. The natural occurrence of Fusarium mycotoxins was surveyed in 39 barley and 46 corn samples from different areas. Five 8-ketotrichothecenes, namely deoxynivalenol (DON), nivalenol (NIV), 4-acetylnivalenol (4-ANIV), 3-acetyldeoxynivalenol (3-ADON), and 4,15-diacetylnivalenol (4,15-DANIV), and zearalenone (ZEA) were detected in barley. DON, NIV, and ZEA were the major contaminants in barley, with mean levels of 170, 1,011, and 287 ng/g, respectively. On the other hand, DON, 15-acetyldeoxynivalenol (15-ADON), NIV, 4-ANIV, 4,15-DANIV, and ZEA were detected in corn samples. DON and 15-ADON were the major contaminants in corn, with mean levels of 310 and 297 ng/g, respectively. The survey indicated that the natural occurrence of monoacetyl-DON and the ratios of NIV to DON in two cereals were different. In addition, this is the first report of the natural occurrence of 4,15-DANIV in cereals.

Transient spontaneous remission in acute promyelocytic leukemia--two case reports

Two cases of spontaneous remission in acute promyelocytic leukemia are reported. They had precedent febrile episodes and subsequent resolution of all clinical and hematological abnormalities occurred after supportive care including administration of various antibiotics. Their remissions lasted for 12 and five months respectively, when they relapsed.

Acute leukemias with unusual immunophenotypes

Over a two-year period, immunophenotypic patterns of 266 acute leukemia cases were analyzed using a panel of tests including TdT, SmIg and 9 surface antigens by the immunofluorescence stains for the assessment of the incidence and grade of phenotypic ambiguity (lineage infidelity) and the possible clinical significance of unusual immunophenotypes. Immunophenotypes were classified into four groups according to the degree of ectopic antigen expression. We classified as Group A (91.7%, 244 of 266 cases) those expressing conventional pattern without ectopic antigen. Group B (3.0%, 8 of 266 cases) was defined to have at least two lineage specific markers and single ectopic antigen. Such a "low grade deviation" did not prevent a definite immunodiagnosis. Group C (4.2%, 11 of 266 cases) revealed a promiscuous coexpression of markers related to different lineages, including two cases (0.8%, 2 cases) of biphenotypic leukemia. Group D (1.1%, 3 cases) included unclassifiable immunophenotypes with no antigen or HLA-DR only expression. Both patients with biphenotypic leukemia and one patient with unclassifiable immunophenotypes failed to respond to induction chemotherapy, suggesting a poor prognosis in these patients. The incidence of acute myelogenous leukemia (AML) cases with one or more ectopic surface antigens was 10 (8.1%) of the 124 AML cases. Ectopic antigen expression was seen in 5 (4%) of the 125 B-lineage acute lymphoblastic leukemia (ALL) cases and 3 (25%) of the 12 T-ALL cases. It is concluded that nearly 95% of cases of acute leukemia cases can be diagnosed accurately with immunophenotyping alone including patients with a mild degree of deviation from expected antigenic patterns.(ABSTRACT TRUNCATED AT 250 WORDS)

pH-inducible beta-glucosidase and beta-glucuronidase of intestinal bacteria

beta-Glucosidase and beta-glucuronidase of human and rat fecal bacteria were induced by cultivation in alkaline media although their growths were not affected. When a bacterium isolated from human feces producing each enzyme was cultured in a medium at pH 5 for 12-15 h and then adjusted to pH 8, beta-glucosidase and beta-glucuronidase were induced 9.2-fold and 11.5-fold, respectively.

Blood gas and electrolyte changes after tourniquet application in total knee replacement surgery

The tourniquet is widely used in upper and lower extremity surgery in orthopedic practice. However, safe working guidelines for the application of the tourniquet are not clearly defined. The use of a tourniquet is an important step in performing total knee arthroplasty, and it seems plausible that mechanical damage is directly related to the height and the duration of the pressure of the tourniquet applied. Even the tourniquet pressure which is widely accepted in clinical practice, if it is applied for several hours, would permanently damage not only tissues directly under the tourniquet but also the muscles and the nerves distal to the tourniquet. The resultant ischemia to limb produces local changes including hypoxemia, acidosis and hyperkalemia. Relatively little is known about the systemic effects of tourniquet release when the patient is undergoing total knee replacement surgery under a general anesthesia. Therefore, we studied the systemic effects. The results were as follows: 1) Approximately five minutes after the tourniquet was released there was a statistically significant increase in mean heart rate.: 2) Serum potassium levels tended to increase significantly until five minutes while the serum sodium level rose significantly only one minute, and the lactate level rose significantly for only two minutes after tourniquet released; 3) PaCO2 increased for five minutes after tourniquet release and remained elevated for 30 minutes; 4) PaO2 did not change significantly two minutes after tourniquet release; 5) The mean pH dropped to 7.34 and remained low for over five minutes.

An experimental intraarticular implantation of woven carbon fiber pad into osteochondral defect of the femoral condyle in rabbit

The defects of the articular cartilage structure are not replaced unless the subchondral plate has been breached. However, following the creation of a defect in the subchondral plate, the area is filled in with a fibrous tissue which gradually transforms to hyaline cartilage. The porous nontoxic materials of both biologic and synthetic origin have reportedly been used as matrices for repairing bone and cartilage. Following implantation, carbon fibre, chemically inert and well-tolerated by the body, induces a proliferation of ordered fibrous tissue. We implanted carbon fiber pads in osteochondral defects in rabbits. Those repairs were compared to control holes with no implants. The pads appeared to induce the gross appearance of a restored joint surface, mechanically strong to loading for periods from 2 to 6 weeks. Also, carbon fiber pads promoted the healing of the osteochondral defects in the rabbit femoral condyle, supplying well-organized cartilagenous tissue over repaired subchondral bone. The use of carbon fiber pads as implant material is suggested for the restoration of articular surface in osteoarthritis and osteochondritis dissecans.

An experimental study of healing of the partially severed flexor tendon in chickens

There is a lack of clinical and experimental studies of the treatment of incompletely transected tendons. The controversy concerning the source of flexor tendon nutrients is of important clinical concern in healing of the injured tendon; thus, the flexor tendon blood supply has cited as a reason for using specific tendon suture techniques, and as a rationale for preserving the superficialis tendon and its vincula during tendon repair surgery. Our knowledge of the normal physiology of digital flexor tendons and the mechanism of their healing process is deficient. The aim of this study was to investigate the relative importance of the synovial fluid and the blood supply respectively for the healing of partially severed flexor tendons. We observed the sequential histological and vascular changes which occur in healing of the partial lacerations in the dorsal and plantar aspects of the tendons. We observed the vascularities of the two partially severed tendon groups after injection of microfil and india ink through the femoral artery. In the healing process there was no sequential histological difference between the dorsal and the plantar severed tendons. The vascularity patterns of the healing tendons were significantly increased and the hypervascularity of dorsal severed tendons was greater than that of plantar severed tendons. Partially severed tendons were completely healed without surgical repair with dense collagen fibers without adhesion in most cases. We concluded from this study that the blood vessels appeared to play a significant role in the healing of the severed flexor tendons. An intact synovial environment did not seem to be required for healing of the severed tendon. It is not necessary to surgically repair the partially severed tendon for prevention of rupture and adhesion.

Autolysed antigen-extracted allogeneic bone for repair of diaphyseal bone defects in rabbits

Autolysed antigen-extracted allogeneic bone (AAA bone) was used to bridge a large osteoperiosteal gap in the diaphysis of the radius of 50 rabbits. Periodic observations of the graft were made clinically, radiologically and histologically every week up to fourteen weeks. The continuity of the radius was evaluated macroscopically and histologically. The AAA bones were progressively resorbed and replaced by the new bone. The bone remodelled to the mature tubular bone and did not undergo absorption during the experimental period. The AAA bone proceeded to be an osteoinductive and osteoconductive material. There were no appreciable histologic signs of immune or foreign body reaction.

The effect of experimental trypsin on the regeneration of hyaline articular cartilage

There is evidence from other studies that some degree of cartilage healing may take place after the initiation of an inflammatory response. It is postulated that the induction of the platelet-cartilage interaction may eventuate in cartilage repair. The treatment of fresh articular cartilage with proteolytic enzymes rendered the tissue active as a platelet aggregant. During platelet aggregation a host of active substances are released which are known to play a role in the inflammatory response (Thompson 1975). This study was undertaken to evaluate the effects of trypsin on the surface injury of rabbit hyaline cartilage. The results were as follows: 1) Hyaline cell regeneration was observed only in the group treated with trypsin and blood; 2) Hyaline cartilage regeneration did not occur in the group treated with a single injection of trypsin or blood; 3) There was no significant damage to the healthy articular cartilage by the single injection of trypsin or blood, or both; and 4) Platelets do not adhere to cartilage and superficial damaged cartilage does not induce platelet aggregation.

Changes in the hyaline articular cartilage after air exposure

The changes of hyaline articular cartilage from rabbits after air exposure were evaluated. The knee joints were exposed to air for periods of thirty minutes to two hours. The animals were killed periodically, at three days, one week and three weeks postoperatively. After sacrifice, the cartilage was removed and prepared for study by light microscopy and electron microscopy. Exposure to room air for thirty minutes produced chondrocyte necrosis in the upper third of the cartilage, and exposure for 60 minutes or longer produced chondrocyte necrosis of the entire thickness of articular cartilage at three days after arthrotomy. But, three weeks after arthrotomy, we could not find any chondrocyte necrosis in any rabbits at varying periods of air exposure. There was no significant change in proteoglycan content between the aired and control cartilage.

CLINICAL RELEVANCE

Exposing cartilage to air can cause transient and reversible cartilage damage. If these changes are not reversible, the orthopedic surgeon should consider avoiding the prolonged exposure of articular cartilage to air, since complete matrix disintegration is known to occur months after chondrocyte necrosis.

Pemphigus foliaceus induced by rifampicin

Pemphigus foliaceus was seen in a patient with pulmonary tuberculosis during rifampicin therapy. The skin lesions were eczematoid patches, flaccid bullae and crusted plaques on the trunk and extremities, histologically showing a high epidermal blister with acantholysis. The diagnosis was confirmed by immunofluorescent studies. After the patient discontinued rifampicin, the skin lesions cleared completely within 5 weeks without any systemic medication.