The microbiology and pathogenesis of infective endocarditis

Some details of 544 episodes of infective endocarditis occurring in 541 patients during 1981 and 1982 are reported. The mean age of patients was 51.6 years and there was a greater proportion of males (2:1). Of the 544 episodes 347 (63%) were due to streptococci, 19% to staphylococci, and 14% to bowel organisms. A wide variety of other organisms were responsible for a few cases, and 10% were culture negative. In 60% the portal of entry of the infection could not be ascertained: 19% were probably of dental origin: 16% arose from the alimentary, genitourinary, or respiratory tracts or from the skin or in association with drug addiction, fractures, or pregnancy; the remaining 5% were related to cardiac or other vascular surgery, cardiac catheterisation, haemodialysis, or other procedures involving the blood stream. Seventy-four (14%) of the 541 patients (mean age 59.0 years) died; the mortality was 30% in staphylococcal cases, 14% in infections due to bowel organisms, and 6% in other streptococcal infections. One hundred and seventy-one (32%) of the patients appeared to have had normal hearts before the onset of illness and another 59 (11%) had cardiac lesions not previously recognised. The aortic valve was the most common site of infection. Ninety (17%) of the patients had prosthetic valves or had undergone other cardiac surgery while 34 (6%) had had a previous episode of infective endocarditis. Nine (1.6%) episodes were not diagnosed until necropsy or operation and 34 (6.3%) required urgent valve replacement.     

The role of interferon in virus-induced diabetes

The repeated administration of interferon (IFN) or an IFN inducer reduced the development of diabetes in mice infected with the D variant of encephalomyocarditis (EMC) virus. Mice treated with the IFN inducer had less infectious virus, fewer pathologic changes, and higher concentrations of immunoreactive insulin in the islets of Langerhans in comparison with untreated mice. Antibody to mouse IFN (MuIFN) suppressed circulating IFN in mice infected with the B variant of EMC virus. Mice treated with antibody to MuIFN had four times more infected islet cells and 10 times more infectious virus in the pancreas compared with untreated mice. Of the surviving animals treated with antibody to MuIFN, approximately 40% developed mild diabetes whereas none of the mice developed diabetes when infected with the B variant of EMC virus alone. The IFN system is an important determinant of the outcome in EMC virus-induced diabetes in mice.     

In vivo microscopy of the cerebral microcirculation using neonatal allografts in hamsters

Studies were performed to characterize the morphology and vascular reactivity of the allografted cerebral microcirculation. Cerebral cortical tissue was allografted into the cheek pouch of the hamster so that cerebral parenchymal vessels could be studied. The vascular morphology was characterized by a large number of looping vessels. The ultrastructural examination indicated viable cerebral tissue containing typical vessels, that is, "tight" junctions, not like those of the cheek pouch. Also, the microvasculature was impermeable to 150, 70, and 20 kDa fluorescein isothiocyanate dextrans. Angiotensin II and norepinephrine caused constriction of the cerebral vessels whereas adenosine caused dilation. Isoproterenol did not affect cerebral arterioles; however, it dilated cheek pouch arterioles. Thus, this preparation provides a satisfactory model for studying the living cerebral microcirculation.     

Clinical and metabolic efficacy of glutamine-supplemented parenteral nutrition after bone marrow transplantation. A randomized, double-blind, controlled study.

OBJECTIVE: To determine whether glutamine-supplemented parenteral nutrition improves nitrogen retention and reduces hospital morbidity compared with standard parenteral nutrition after bone marrow transplantation. DESIGN: Double-blind, randomized, controlled clinical trial. SETTING: University teaching hospital. PATIENTS: Forty-five adults receiving allogeneic bone marrow transplants for hematologic malignancies. INTERVENTION: Parenteral nutrition was initiated the day after bone marrow transplantation (day 1). The experimental solution was supplemented with L-glutamine (0.57 g/kg body weight per day) and provided estimated requirements for energy and protein. The control solution was a standard, glutamine-free, isonitrogenous, isocaloric formula. MEASUREMENTS: Nitrogen balance was determined between days 4 and 11 in the initial 23 patients. The incidence of clinical infection and microbial colonization, time until bone marrow engraftment, indices of clinical care, and other data related to hospital morbidity were recorded for all patients. RESULTS: The glutamine-supplemented patients (n = 24) were clinically similar to the controls (n = 21) at entry. Nutrient intake was similar in both groups; however, nitrogen balance was improved in the glutamine-supplemented patients relative to the controls (-1.4 +/- 0.5 g/d compared with -4.2 +/- 1.2; P = 0.002). Fewer experimental patients developed clinical infection (three compared with nine in the control group; P = 0.041), and the incidence of microbial colonization was also significantly reduced. Hospital stay was shortened in patients receiving glutamine supplementation (29 +/- 1 d compared with 36 +/- 2 d; P = 0.017). CONCLUSION: Patients receiving glutamine-supplemented parenteral nutrition after bone marrow transplantation had improved nitrogen balance, a diminished incidence of clinical infection, lower rates of microbial colonization, and shortened hospital stay compared with patients receiving standard parenteral nutrition. These effects occurred despite no differences between groups in the incidence of fever, antibiotic requirements, or time to neutrophil engraftment.     

Matrix metalloproteinase-1 and skin ageing in smokers

Smokers look older than non-smokers of the same age. We have compared the concentrations of mRNA for matrix metalloproteinase 1 (MMP-1) in the buttock skin of smokers and non-smokers with quantitative real-time polymerase chain reactions. MMP-1 degrades collagen, which accounts for at least 70% of the dry weight of dermis. We report significantly more MMP-1 mRNA in the skin of smokers than non-smokers whereas no difference was seen for the tissue inhibitor of metalloproteinases 1 (TIMP-1) or the housekeeping gene GAPDH (glyceraldehyde-3-phosphate dehydrogenase). We suggest that smoking-induced MMP-1 might be important in the skin-ageing effects of tobacco smoking.     

The microbiology and pathogenesis of infective endocarditis.

Some details of 544 episodes of infective endocarditis occurring in 541 patients during 1981 and 1982 are reported. The mean age of patients was 51.6 years and there was a greater proportion of males (2:1). Of the 544 episodes 347 (63%) were due to streptococci, 19% to staphylococci, and 14% to bowel organisms. A wide variety of other organisms were responsible for a few cases, and 10% were culture negative. In 60% the portal of entry of the infection could not be ascertained: 19% were probably of dental origin: 16% arose from the alimentary, genitourinary, or respiratory tracts or from the skin or in association with drug addiction, fractures, or pregnancy; the remaining 5% were related to cardiac or other vascular surgery, cardiac catheterisation, haemodialysis, or other procedures involving the blood stream. Seventy-four (14%) of the 541 patients (mean age 59.0 years) died; the mortality was 30% in staphylococcal cases, 14% in infections due to bowel organisms, and 6% in other streptococcal infections. One hundred and seventy-one (32%) of the patients appeared to have had normal hearts before the onset of illness and another 59 (11%) had cardiac lesions not previously recognised. The aortic valve was the most common site of infection. Ninety (17%) of the patients had prosthetic valves or had undergone other cardiac surgery while 34 (6%) had had a previous episode of infective endocarditis. Nine (1.6%) episodes were not diagnosed until necropsy or operation and 34 (6.3%) required urgent valve replacement.     

Preload dependency of the time interval between the onset of mitral inflow and the early diastolic annular motion: a hemodialysis-related preload reduction study.

BACKGROUND: The novel parameter T(E-E'), which is the time interval between the onset of the early diastolic mitral inflow velocity (E) and the early diastolic mitral annular velocity (E'), is reported to be related to the constant of the left ventricular (LV) relaxation, and T(E-E') is also reported to be useful for predicting the LV filling pressure. METHODS AND RESULTS: To investigate the effect of preload reduction via hemodialysis on T(E-E'), 28 pairs of echocardiographic evaluations were performed just before and immediately after hemodialysis, including the measurement of the T(E-E') as well as measurement of the conventional echocardiographic parameters. The baseline T(E-E') was 17.9 +/-28.1 ms, which correlated with the ratio of E/E' (r=0.49, p=0.008). After hemodialysis, T(E-E') was shortened to -3.2+/-34.1 ms, which was a significant change from baseline (p=0.001). CONCLUSIONS: As T(E-E') is a preload dependent parameter, the intravascular volume status should be taken into account when the clinical application of T(E-E') is considered as an index of LV relaxation.     

Composite neuroendocrine and adenocarcinoma of the common bile duct associated with Clonorchis sinensis: a case report

The biliary tract has neuroendocrine cells of endoderm origin similar to the gastrointestinal tract, however neuroendocrine tumors of the biliary tract are rare. We report a composite glandular-endocrine cell carcinoma of the common bile duct in a 64-year-old Korean man which was associated with Clonorchis sinensis. The patient complained of right upper quadrant abdominal pain. Several parasites of Clonorchis sinensis were removed during the percutaneous transbiliary drainage. Endoscopic retrograde cholangiopancreatography revealed a polypoid mass (3 x 3 cm) with central ulceration in the common bile duct. Pancreaticoduodenectomy was performed. Microscopic examination of the tumor revealed a composite small cell neuroendocrine carcinoma and adenocarcinoma. The small cell carcinoma component showed positive reaction to chromogranin A and neuron-specific enolase and it was located mainly in the deeper portion of the mass. The well-differentiated adenocarcinoma component showed a positive reaction to carcinoembryonic antigen and it was situated in the superficial portion of the mass. Exclusively, the small cell component metastasized to the lymph node. It is suggested that this tumor could arise from a multipotential stem cell and showed neuroendocrine and glandular differentiation and that Clonorchis sinensis could be a predisposing factor, as in cholangiocarcinoma.