Stage-associated risk of transmission of the Lyme disease spirochete by European Ixodes ticks.

To more closely define the risk of infection by the agent of Lyme disease in Europe, we determined whether spirochetal prevalence increases throughout the development of the Ixodes ricinus vector tick. Of all ticks that could be flagged from vegetation, I. ricinus were by far the most abundant. Spirochetal infection rates in the adult stage of this tick (15%) are no higher than those in nymphs (18%) but greatly exceed those in larvae (0.7%). This tick therefore appears to attain infection mainly from the host of its larval stage, generally feeds on hosts that are noncompetent as reservoirs in its nymphal stage, and rarely inherits infection. Risk of human infection mainly derives from contact with the nymphal stage of the vector tick because the larva is rarely infected and the adult is large enough to be noticed and promptly removed.

What's new in lung physiology? Pulmonary vessel regulation/non-respiratory metabolic lung functions.

Whereas in the last few decades respiratory functions of the lung occupied a central role in research activity, current interests are concentrating more and more on non-respiratory functions. The present small overview concerns itself with vasoregulation and metabolic operations of the lung. A series of important review articles on this topic convey extensive information.

Immunohistochemical demonstration of tumor-associated antigens in prostatic carcinomas of various histological differentiations.

Prostate acid phosphatase (PAP), prostate-specific antigen (PSA), carcinoembryonic antigen (CEA) and keratin were determined immunohistochemically in paraffin sections from 64 prostatic carcinomas fixed in formalin according to the conventional method. The results obtained with PSA led to the correct diagnosis of prostatic carcinoma in 90.7% of the cases. 80.3% of the diagnoses obtained with PAP were correct. The intensity of the staining of the marker decreased with increasing differentiation. 3 utricular carcinomas were positive for PAP and PSA. CEA and keratin may be considered unspecific tumor markers only. However, metaplastic squamous epithelium from poorly differentiated carcinomas was always positive for keratin. PAP and PSA are also suitable for differentiating between tumors of prostatic and nonprostatic origin and could thus be successfully used to determine immunohistochemically the histogenesis of 15 invasive, poorly differentiated carcinomas of the prostate and bladder. PSA again proved to be a more specific epithelial marker than PAP.

Influence of fenofibrate on cellular and subcellular liver structure in hyperlipidemic patients.

The administration of lipid-lowering drugs to rodents, notably those related to clofibrate, rapidly provokes a hepatic response characterized by hepatomegaly, proliferation of smooth endoplasmic reticulum and proliferation of peroxisomes in hepatocytes. In some studies hepatocellular carcinoma has been found in rats or mice exposed for their entire life-span to high dose levels of various fibrates. In the present study liver biopsy samples were obtained from 38 hyperlipidemic patients, 28 of whom had been receiving fenofibrate for between 2 months and approximately 3 years (mean values: males 1.79, females 1.98 years). The remaining 10 patients had never been treated with a lipid-lowering drug. Examination of the biopsy samples by a variety of optical techniques and by electron microscopy failed to reveal any difference between the groups. Peroxisomes were relatively rare, there being no evidence of the clear proliferation seen in rodent studies. Other microscopic features of interest were some variation of nuclear size, mitochondria containing paracrystalline inclusions, dilated endoplasmic reticulum associated with reduced amounts of rough endoplasmic reticulum, and the presence of lipid droplets in the liver cells. However, these variations from normal were in general not much more apparent in samples from the fenofibrate-treated patients than in the untreated group. Light- and electron-microscopic observations did not suggest liver intoxication or a carcinogenic pattern.

Long-term fate of lung autografts charged with providing total pulmonary function. I. Light and electron microscopic studies.

Two groups of dogs underwent light and electron microscopic examination of both lungs up to five years after left lung autotransplantation. In one group of four dogs that had undergone ligation of the right pulmonary artery at the time of left lung autotransplantation, no generalized or consistent lesions were present in the transplant except for slight distension of net capillaries and slight capillary basement membrane thickening. Aside from theseminor changes which were probably of no functional significance, most areas of lung examined up to five years after transplantation were normal. In the second group of four dogs that did not have contralateral pulmonary artery ligation at the time of left lung autotransplantation, no consistent abnormality was present in either the transplanted left or nontransplanted right lung. In three animals in this group, widespread normal areas were present bilaterally up to five years after transplantation. One animal in this group had focal changes consistent with chronic pulmonary disease in both of its lungs. Thus, transplanted lungs do not necessarily develop significant late pathologic lesions.

[Scanning electron microscope study of the lung epithelium of the rabbit during ontogenesis]. / Rasterelektronenmikroskopische Untersuchungen der Lungenepithelien des Kaninchens während der Ontogenese.

The development of the bronchial and alveolar epithelium was observed in rabbits from the 15th day post conception until the time of birth with the scanning electron microscope. In the pseudoglandular phase, primitive bronchi proliferate in the mesenchyme. The epithelial cells are not differentiated and have single cilia. After retraction of these single cilia cell differentiation begins. Flat cells densely populated with cytopodia can be recognized on the 22nd day, ciliated cells on the 23rd day post conception. Both are located in the bronchi near the hilus. In the canalicular phase of development, the differentiation of the mucoid cells and the Clara-cells begins. The interstitial connective tissue develops more and more capillaries. The alveolar phase begins around the 26th day p. c. The lung capillaries reach the alveolar epithelial cells and arrange themselves directly beneath the epithelial basement membrane. This "alveolarization" of the lung tissue starts in the centre of the lung lobules and proceeds to the periphery. After the 26th day post conception the alveolar epithelial cells retract their single cilium and at the same time become type I or type II pneumocytes. The undifferentiated entodermal stem cell of the alveolar epithelium is the pneumoblast.

[Primary vascular pulmonary hypertension and ovulation inhibitors]. / Primär vaskuläre pulmonale Hypertonie und Ovulationshemmer

PIP: The case of a 32-year-old woman who had used oral contraceptives and died from primary vascular pulmonary-hypertension (PVPH) is discussed. A case of this type had never been reported before and the relationship between the occurrence of PVPH and oral contraceptive use is discussed. A relationship between oral contraceptive use and venous thrombosis of the lower extremities has been demonstrated. The direct effect of oral contraceptives on blood vessels has been shown in animal experiments and pathological-histological studies. Clinical studies indicate a relationship between pulmonary hypertension and oral contraceptive use.^ieng

Alveolar lavage cytology in transplanted lungs. I. Staining methods and findings in dogs with autografts and allografts without immunosuppression.

Alveolar lavages were performed repetitively on the normal and transplanted lungs of dogs that had recieved autografts or allografts without immunosuppression. One half of the lavage returns was fixed as a cytologic smear; the other half was subjected to semi-thin section or electron microscopic examination. Of the staining methods was used, the periodic acid-Schiff (PAS) and Giemsa techniques were best for differentiating and counting cells. The Ladewig technique was best for evaluating the presence and location of fibrin. After autotransplantation, the proportion of so-called alveolar marcophages increased, reached a peak in 4 to 7 days, and then returned to normal. Phagocytized fibrin increased for the first postoperative week, but not extracellular fibrin was ever observed. After allotransplantation, a progressive decrease in the proportion, size, and vacuolization of so-called alveolar macrophages was noted along with an increase in extracellular fibrin. Intracellular fibrin could be detected only up to the third day. These findings define adequate methods for preparing and staining material obtained from diagnostic alveolar lavages, and they suggest that the procedure may serve as an index of lung allograft rejection.

Corticosteroids in clinical and experimental lung transplantation.

Lung allograft rejection can usually be diagnosed by the appearance of infiltrates on plain chest roentgenograms when these are interpreted in the light of other clinical and bacteriologic information. Large pulsed intravenous doses of methylprednisolone were usually effective in reversing lung allograft rejection that occurred in immunosuppressed dogs. In 10 of 15 animals the presence of moderate to severe rejection and its effective reversal with treatment were documented with roentgenograms and histologic sections. This ability to reverse the manifestations of lung allograft rejection, when they occur, has helped in the management of human lung allograft recipients.