A mouse model of pneumonitis induced by Chlamydia trachomatis: morphologic, microbiologic, and immunologic studies

Swiss-Webster white mice were infected with Chlamydia trachomatis organisms through intranasal inoculation. It was found that a typical interstitial pneumonitis could be induced. Histopathologic findings showed that the lung infiltration was predominantly polymorphonuclear cells and was most prominant on Day 2. The cellular infiltrate gradually changed to mononuclear cells after Day 3. Intracytoplasmic inclusions were frequently found in the interstitial cells and occasionally in the bronchial epithelial cells. Typical chlamydial bodies (elementary, intermediate, and reticulate forms) were identified by electron microscopy. The organisms were recovered from mouse lungs on Days 1--7, with the highest yields on Day 2. This correlated with the peak of lung infiltration seen by histologic examination. Antibodies specific to the infecting immunotype began to appear between Day 7 and Day 10 after inoculation and lasted until Day 35 without a decline in titers. A delayed hypersensitivity reaction was observed by footpad test from Day 5 to Day 21, with the peak reaction at Day 7. This study showed that the mouse model could be used to study the immunopathogenesis of C trachomatis infection.

The effect of a body burden of methylmercury on hepatic regeneration

The model of hepatic regeneration is chosen to study the effect of methylmercury burden on cell proliferation. The results show that chronic methylmercury burden impedes the rate of thymidine incorporation during the process of DNA synthesis. At 24 hours after partial hepatectomy, thymidine incorporation in the mercury exposed rats is 53% of the controls. Counts of labeled hepatocytes in radioautographic preparations also support this observation. This remarkable difference in DNA synthetic activity at 24 hours also reflects in the DNA content and liver, weights at 72 hours after partial hepatectomy (Liver weights 2.36 +/- 0.21 gm/100 gm B. W. vs. 2.67 +/- 0.31 gm/100 B. W., P < 0,05; DNA contents 160.78 +/- 36.76 microgram/gm vs. 214.80 +/- 37.908 microgram/gm, P < 0.05). After two weeks, no significant difference is noted in liver weight, DNA content and synthetic activity. On the other hand, protein content and biosynthesis in the liver of methylmercury burdened rats shows no significant difference from the controls in all the periods studied. From these data it is concluded that the dividing fraction of hepatocytes is reduced in methylmercury-treated group at an early stage of regeneration when cell proliferation is most active.

Mechanisms of prolongation of pre-ejection period in patients with left ventricular disease

In order to determine the mechanism underlying prolongation of the pre-ejection period in patients with left ventricular disease, 11 patients with congestive cardiomyopathy and 29 with coronary artery disease, 10 of whom were taking beta-adrenergic blocking drugs, were studied non-invasively. Recordings of carotid pulse, and apex, phono-, and echocardiogram were obtained. In the absence of treatment with beta-blocking drugs, prolongation of pre-ejection period correlated closely with incoordinate left ventricular wall movement during isovolumic contraction assessed from simultaneous apex and echocardiograms. There was no correlation between pre-ejection period index (PEPI) and end-diastolic dimension and PEPI correlated poorly with fractional shortening and peak Vcf. A PEPI of greater than 140 ms was associated with incoordinate contraction in all but one case, and of less than 140 ms with normal contraction in all. Therapeutic doses of beta-blocking drugs caused prolongation of PEPI to a greater extent than would have been predicted from wall movement during isovolumic contraction. Incoordinate left ventricular contraction and a negative inotropic effect both therefore prolong PEPI, but by different mechanisms, whose effects can be separated in individual patients using non-invasive methods based on echocardiography.

The effect of methylmercury on isolated cardiac tissues

The effect of methylmercury hydroxide (MMH) on the frequency of spontaneously beating atrial-SA node and on the isometric tension of electrically stimulated left atrial (1 Hz) preparation isolated from rats were investigated. The tissues were also fixed for ultrastructural study at the end of the experiments. We found that MMH, at low doses (0.5 and 2ppm), increased the frequency of contractions and the isometric tension of isolated atria and decreased the isometric tension of isolated papillar muscles, and at higher doses (greater than 2ppm), decreased all the above parameter. Morphologically, there were dilation and swelling of mitochondrial and sarcoplasmic reticulum. Occasionally, deposits of amorphous material in the mitochondria and myofibrillary degeneration of myocardial fibers were noted. It is concluded the MMH has direct effect on intracellular organelles (mitochondria, sarcoplasmic reticulum, and myofibril) of myocardial tissue and induces functional changes of atria and papillary muscles

Interaction of delta-chymotrypsin with proflavine

A 1:1 molar stoichiometry has been found for the noncovalent bonding of proflavine with δ-chymotrypsin. The dissociation constant at pH 7.6 is 0.025 mM which is similar to that found by Glazer for the reaction of proflavine with α-chymotrypsin. The difference spectrum produced by the proflavine–δ-chymotrypsin interaction has been studied as a function of pH. It would appear that a group with pK of approximately 6.5 is involved.

Radioimmunoassay of follicle-stimulating (FSH) and luteinizing (LH) hormones by chromatoelectrophoresis

Procedure for the radioimmunoassay of FSH and LH using chromatoelectrophoresis for the separation of antibody-bound and free labeled hormone is described. Diurnal variation in FSH and LH levels of normal men and women in follicular and luteal phases of the cycle is reported. The diurnal variation was not abolished in three women taking contraceptive medication and in two women in postmenopause. The diurnal variation of FSH and LH in plasma is compared with that of cortisol, dehydroepiandrosterone and testosterone. It is suggested that diurnal variation of FSH and LH may be independent of a normally functioning pituitary-gonadal axis; however, steroidal feed-back may have a regulatory effect on the magnitude of the diurnal variation. The plasma levels of FSH and LH in normal subjects during normal menstrual cycles as well as in patients with endocrinopathies obtained in our laboratory by radioimmunoassay are compared with those obtained by both radioimmunoassay and bioassay by other investigators.