The need for an integrated approach for chronic disease research and care in Africa.

With the changing distribution of infectious diseases, and an increase in the burden of non-communicable diseases, low- and middle-income countries, including those in Africa, will need to expand their health care capacities to effectively respond to these epidemiological transitions. The interrelated risk factors for chronic infectious and non-communicable diseases and the need for long-term disease management, argue for combined strategies to understand their underlying causes and to design strategies for effective prevention and long-term care. Through multidisciplinary research and implementation partnerships, we advocate an integrated approach for research and healthcare for chronic diseases in Africa.

Matrix metalloproteinase-2 and -9 involvement in canine tumors.

Matrix metalloproteinases (MMPs) are a family of enzymes implicated in the degradation and remodeling of extracellular matrix and in vascularization. They are also involved in pathologic processes such as tumor invasion and metastasis in experimental cancer models and in human malignancies. We used gelatin zymography and immunohistochemistry to determine whether MMP-2 and MMP-9 are present in canine tumors and normal tissues and whether MMP production correlates with clinicopathologic parameters of prognostic importance. High levels of pro-MMP-9, pro-MMP-2, and active MMP-2 were detected in most canine tumors. Significantly higher MMP levels were measured in canine tumors than in nontumors, malignancies had higher MMP levels than benign tumors, and sarcomas had higher active MMP-2 than carcinomas. Cartilaginous tumors produced higher MMP levels than did nonsarcomatous malignancies, benign tumors, and normal tissues, and significantly greater MMP-2 than osteosarcomas and fibrosarcomas. Pro-MMP-9 production correlated with the histologic grade of osteosarcomas. The 62-kd form of active MMP-2 was detected only in high-grade, p53-positive, metastatic malignancies. Zymography proved to be a sensitive and quantitative technique for the assessment of MMP presence but has the limitation of requiring fresh tissue; immunohistochemistry is qualitative and comparatively insensitive but could be of value in archival studies. MMP presence was shown in a range of canine tumors, and their link to tumor type and grade was demonstrated for the first time. This study will allow a substantially improved evaluation of veterinary cancer patients and provides baseline information necessary for the design of clinical trials targeting MMPs.

Clinical and pathologic relevance of p53 index in canine osseous tumors.

The clinicopathologic value of the immunohistochemical (IHC) expression of p53 protein was evaluated in 167 canine osseous tumors. p53 staining frequency and intensity in tumor cells was expressed as a p53 index. p53 index was significantly higher in osteosarcomas than in other sarcomas, chondrosarcoma, multilobular tumor of bone, and tumors initially misdiagnosed as osteosarcomas as well as in appendicular versus axial and in distal versus proximal osteosarcomas. A strong correlation is demonstrated between the p53 index and a range of clinicopathologic parameters in osteosarcoma, including the tumor site, histologic grade and score, mitotic index, degree of tumor necrosis, and pleomorphism. Chondroblastic osteosarcomas had significantly higher and telangiectatic osteosarcomas significantly lower p53 index than did osteosarcomas belonging to other histopathologic subtypes, a fact that tends to reinforce the perception of these osteosarcomas as distinct clinicopathologic entities. Entire males had higher p53 index than did neutered males. p53 index was higher in Rottweilers than in Great Danes and Terriers, confirming breed susceptibilities to osteosarcoma. p53 index showed no association with age, primary or secondary site status, or the presence of metastases or other tumor types. Biopsy samples had a higher p53 index than did postmortem samples, either because of differences in sample processing or the possibility that p53 overexpression is more evident at the earlier stages of osteosarcoma pathogenesis, presumably represented by the biopsy material. IHC examination for p53 and the derived index has the potential to be used as an additional diagnostic tool and prognostic indicator for osseous tumors.

A new phytase expressed in yeast effectively improves the bioavailability of phytate phosphorus to weanling pigs.

We have recently expressed a new phytase enzyme in a yeast system. Three experiments with a total of 140 weanling crossbred pigs were conducted to examine the efficacy of this enzyme in improving the bioavailability of phytate-P in corn-soybean meal diets to young pigs. Experiment 1 compared the efficacy of this new phytase with a commercially available phytase (Natuphos, BASF) for 4 wk at an inclusion level of 1,200 U/kg of diet. Experiment 2 compared the responses of pigs to four doses of the new phytase supplementation (300, 600, 900, and 1,200 U/kg of diet) for 4 wk. Experiment 3 compared the efficacy of this new phytase and Natuphos at a marginally optimal dose (700 U/kg of diet) for 5 wk. A group of pigs were fed the P-deficient basal diet as a negative control in Exp. 1, and a group of pigs were fed the basal diet plus .17 or .22% inorganic P as a positive control in all experiments. In Exp. 1, pigs fed the two sources of phytase had similar ADG (564 vs 567 g), gain/feed (.597 vs .589), plasma inorganic P concentrations (8.9 vs 8.4 mg/dL), and mobility scores (4.25 vs 4.46) that were higher (P < .05) than those of the negative control. In Exp. 2, plasma inorganic P concentration was a fairly linear response to the phytase dose (r > .83) at wk 1 and 2. Overall ADG of pigs also tended to increase with the phytase dose (P = .15). In Exp. 3, pigs fed the two sources of phytase had ADG (483 vs 506 g) similar to that of the positive control (508 g). These two groups also had similar plasma inorganic P concentrations (7.7 vs 7.4 mg/dL) that were lower (P < .05) than those of the positive control group (9.7 mg/dL). There was no significant effect of dietary treatments on ADFI in all three experiments. In conclusion, our new phytase was as effective as Natuphos, at the inclusion level of 700 or 1,200 U/kg of a P-deficient, corn-soybean meal diet, in improving phytate-P utilization by young pigs.

High molecular mass complexes of aquatic silk proteins.

Little is known about specific protein protein associations that take place during formation of Chironomus tentans silk. The aim of this study was to learn if C. tentans salivary glands contain biochemically discrete silk protein complexes. Examination of native extracts by non-denaturing agarose gel electrophoresis and immunoblotting revealed two SDS-resistant complexes: C1a, nominally containing silk proteins spIa, sp185 and sp140, and C1b, containing spIb, sp185 and sp140. The data also implied that C1a and C1b can further associate into SDS-sensitive homo- or hetero-oligomers. Sedimentation of extracts in preparative glycerol gradients resulted in a heterogeneous distribution of C1a and C1b centered near 30S. Examination of gradient fractions by denaturing polyacrylamide gel electrophoresis and immunoblotting indicated that C1a and C1b co-sediment with spIs, sp185, and sp140; however, these fractions also contained sp40, sp17 and sp12. In contrast, two other silk proteins sedimented throughout the gradient. Electron micrographs of a complex-containing fraction showed discrete, sometimes oligomeric lattice-like structures that, over time, assembled in vitro into multistranded beaded fibers. It is proposed that C1a and C1b are quaternary structures that are intermediates in the assembly pathway of C. tentans silk.

Pharmacokinetics of cephalexin in cats after oral administration of the antibiotic in tablet and paste preparations.

OBJECTIVE: To determine the bioequivalence of a paste formulation of cephalexin with that of the tablet form. DESIGN: A two-way cross-over study. ANIMALS: Ten adult cats of mixed breed. PROCEDURE: The cats, randomly allocated to two groups, received either the paste preparation or the tablet orally at 12-hour intervals for 48 h before a 12-hour blood collection period. Two weeks later the treatments were reversed and the blood sampling repeated. The serum concentrations of the antibiotic were determined. The pharmacokinetic factors were analysed using a computer. RESULTS: There were no significant differences between the peak concentration of cephalexin, or the other pharmacokinetic factors obtained from the tablet and paste formulations. The serum profiles of cephalexin following four 12-hourly doses of each formulation were similar with the peak serum values occurring at approximately 2 h after administration. CONCLUSION: The paste formulation and the tablet form are bioequivalent.

A comparison of zidovudine, didanosine, zalcitabine and no antiretroviral therapy in patients with advanced HIV disease.

Three nucleoside analogues, zidovudine (AZT), didanosine (ddI), and zalcitabine (ddC), are approved for use in the treatment of patients with HIV infection. This retrospective study compares the 3 drugs and examines the overall utility of antiretroviral therapy by way of comparisons to a no treatment (No Rx) group in patients with advanced HIV disease. Patients with advanced HIV disease were enrolled in didanosine (August 1989-December 1990) or zalcitabine (October 1990-February 1992) expanded access programmes; continued on zidovudine treatment despite fulfilling criteria for zidovudine failure or intolerance; or maintained on no antiretroviral treatment. Statistical analysis revealed that patients on nucleoside analogue therapy had fewer opportunistic infections (P = 0.001) than those who received no antiretroviral treatment. The Kaplan-Meier 12-month estimate of survival was significantly longer among patients who switched from zidovudine to zalcitabine but not among patients who switched to didanosine, when compared to the other 2 groups (P = 0.05).

Value of ultrasound and liver function tests in determining the need for endoscopic retrograde cholangiopancreatography in unexplained abdominal pain.

The value of serum liver function tests and abdominal ultrasound as screening tests of the need for endoscopic retrograde cholangiopancreatography (ERCP) was determined in patients with unexplained abdominal pain without associated jaundice. In 1989 and 1990 1005 ERCPs were undertaken, of which 138 (14%) were for this indication. The duct or ducts of interest were delineated by ERCP in 95% of patients. The lesions found were bile duct stones in 10 patients, chronic pancreatitis in five, pancreatic carcinoma in one, peptic ulcer or duodenitis in four. A satisfactory ultrasound examination had been performed in 94% of patients. For chronic pancreatitis, its sensitivity was 60% and specificity 95%. For choledocholithiasis, the ultrasonic detection of duct dilatation or stones had a sensitivity of 90% and specificity of 86%. Of the liver function tests, the alkaline phosphatase was more sensitive (67%) than the transaminases (44%) in indicating the presence of bile duct stones and had a high specificity (95%). None of the 10 patients with duct stones had normal ultrasound and normal alkaline phosphatase. Thus it was found that demonstration of a normal common bile duct by abdominal ultrasound and normal serum alkaline phosphatase together have 100% specificity in excluding bile duct stones. Using such knowledge over the two year period of this study would have spared 36 patients the need for ERCP.

Effects of exercise stress on various immune functions in horses.

Chemotactic locomotion and luminol-dependent chemiluminescence of neutrophils, mitogen-induced lymphocyte blastogenesis, serum cortisol concentration, immunoglobulin quantification, and leukocyte counts were determined to evaluate the effect of a single strenuous exercise in horses. Increased serum cortisol concentration (P less than 0.01) and an increased neutrophil-to-lymphocyte ratio (P less than 0.05) indicated that horses had been stressed. The chemotactic index and peak chemiluminescence production decreased significantly (P less than 0.05 and P less than 0.01, respectively) 1 day after exercise. Mitogen-induced blastogenesis of lymphocytes and serum immunoglobulin values remained unchanged in response to exercise. Results of this study indicated that a single bout of exercise may transiently impair neutrophil antimicrobial functions and nonspecific defense mechanisms, but not specific immunity in horses.

Septicaemia after colonoscopy in patients with cirrhosis.

Two patients with ulcerative colitis and chronic active hepatitis with cirrhosis, who developed Gram negative septicaemia after colonoscopy are described. These and two similar reported cases indicate that giving prophylactic antibiotics to patients with cirrhosis undergoing colonoscopy should be considered, particularly when the cirrhosis is advanced.

Plasma beta endorphin in cirrhosis and renal failure.

Whether the plasma concentration of beta endorphin was increased in hepatic cirrhosis like that of smaller opioid peptides methionine enkephalin and leucine enkephalin was determined. Its concentration in chronic renal failure was also measured. Plasma beta endorphin was not significantly raised in cirrhotic patients with or without ascites (medians 5.2 pmol/l and 4.7 pmol/l respectively) compared with disease control subjects (4.9 pmol/l) and healthy control subjects (4.9 pmol/l). In contrast, the peptide was increased 2.5 fold (p less than 0.001) in chronic renal failure (12.4 pmol/l) and was found in many of these patients' urine. The data are compatible with the hypothesis that the liver may play an important role in the elimination of opioid peptides of octapeptide size or less but not the larger peptides such as beta endorphin.

Severe thrombocytopenia after paracetamol overdose.

Two patients with severe thrombocytopenia after paracetamol overdose are described. The platelet count was lowest two days after the overdose. Neither leucopenia nor anaemia occurred.

Effect of strenuous exercise stress on chemiluminescence response of equine alveolar macrophages.

Bronchoalveolar lavage samples were collected using a fibreoptic endoscope from horses at specified times before and after single bouts of exercise. Lucigenin-dependent phagocytic chemiluminescence was used to assess the effect of exercise on the alveolar macrophage metabolic activity in response to stimulation by opsonised zymosan. A profound suppressive effect on the chemiluminescence production was present throughout the first three days after exercise. However, the cellular composition of lavage fluids was not altered by the exercise. It is suggested that strenuous exercise may jeopardize the antimicrobial function of alveolar macrophages which may lead to an increase in susceptibility to infection.

Plasma leucine enkephalin is increased in liver disease.

Plasma methionine enkephalin is increased in liver disease and may contribute to some of the clinical manifestations of hepatic failure. To determine if another 'small' opioid peptide is increased in the plasma of patients with liver disease, leucine enkephalin was measured by radioimmunoassay. Its plasma concentration was raised approximately five-fold in patients with acute liver disease (median 1490 pmol/l, range 830-2420) and three-fold in patients with cirrhosis with ascites (960 pmol/l, 470-2900), compared with disease controls (325 pmol/l, 180-740) and healthy controls (305 pmol/l, 180-560). The increase in plasma leucine enkephalin was proportional to the degree of liver damage, as judged in the patients with acute liver disease by its correlation with the prothrombin time (r = 0.691, p less than 0.01) and alanine aminotransferase (r = 0.502, p less than 0.05), and in the patients with cirrhosis by its negative correlation with the plasma albumin (r = -0.743, p less than 0.001). It is unclear whether the raised plasma leucine enkephalin in liver disease is a consequence of diminished hepatic inactivation, increased secretion from sympathetic nerves and adrenal glands, or both.

Fatal variceal haemorrhage after paracetamol overdose.

A patient is described where oesophageal varices developed and bled 13 days after a paracetamol overdose. The bleeding was unresponsive to medical management and proved fatal. There was no evidence that the patient had pre-existing liver disease. At necropsy the liver showed severe acute parenchymal necrosis but chronic lesions were absent. The portal vein and hepatic veins were patent.

Variceal bleeding is associated with reduced risk of severe cholestasis in primary biliary cirrhosis.

To test the hypothesis that, in primary biliary cirrhosis, bleeding from oesophageal varices implies a reduced risk that a patient will subsequently develop severe cholestasis, the case records of 76 patients with this condition who had died were examined. Fifty-nine patients (78 per cent) had died solely or largely as a consequence of liver disease. Their median survival from the onset of symptoms was 72 months. Most died from either hepatic failure with marked jaundice, infected ascites or variceal bleeding. Fifteen patients had a plasma bilirubin less than 100 mumol/l at the time of death. Twenty-eight patients had had variceal bleeding. Compared with the remaining 31 who had also died from cirrhosis, the patients who had bled from varices survived longer, were much less likely to die of hepatic failure and to become severely jaundiced but were more likely to develop fatal infected ascites.

Methionine enkephalin is increased in plasma in acute liver disease and is present in bile and urine.

Plasma immunoreactive methionine enkephalin is increased in cirrhosis. To determine whether it was increased in acute liver disease and chronic renal failure and whether the peptide was present in bile and urine, it was measured by radioimmunoassay in appropriate samples. Plasma immunoreactive methionine enkephalin, while at its peak in 15 patients with acute liver disease (median 425 pmol/l, range 220-1460), was approximately six times greater (P less than 0.001) than in 15 patients with chronic renal failure (70 pmol/l, 50-140), 15 controls with other diseases (75 pmol/l, 50-115) and 15 healthy controls (65 pmol/l, 50-95). In eight of the patients recovering from acute liver disease, the decline of the peptide's plasma level correlated with that of the alanine aminotransferase (r = 0.813, P less than 0.01) and prothrombin time (r = 0.682, P less than 0.05) measured in the simultaneously taken blood. Immunoreactive methionine enkephalin was found to be excreted in bile and urine. The possibility that increased plasma methionine enkephalin, and possibly other opioid peptides, may contribute to some of the manifestations of acute liver failure is worthy of further investigation.