Neuroendocrine control of the postpartum period

This postpartum period is characterized by stimulation of lactation and suppression of ovulation. During pregnancy a number of hormonal changes prepare the breasts for lactation following delivery. The process of lactation is functionally related to the suppression of ovulation. These two physiologic changes observed in the puerperium are considered in detail in this review.

An analysis of the direct effects of gossypol on human spermatozoa

The direct effects of gossypol and its acetic acid adduct, on the movement and functional competence of human spermatozoa were investigated employing exposure times of 1, 5 or 15 min and concentrations of 50 microM, 500 microM and 1000 microM. These compounds markedly reduced the motility, velocity, frequency of sperm head rotation and linearity of sperm progression, the most significant effects being observed with gossypol acetic acid on populations of 'capacitated' spermatozoa. Significant direct effects of gossypol on the ability of human spermatozoa to penetrate both cervical mucus and zona-free hamster ova were also observed, which were independent of any effects on motility. These results reinforce the notion that gossypol may serve a contraceptive role in the female as a 'spermicidal' agent, and suggest that this compound may also be of scientific value as a probe for identifying and isolating functionally important components of the human spermatozoon.

The influence of medium composition, osmolarity and albumin content on the acrosome reaction and fertilizing capacity of human spermatozoa: development of an improved zona-free hamster egg penetration test

The influence of medium composition, osmolarity and albumin concentration on the ability of human spermatozoa to undergo the acrosome reaction and penetrate zona-free hamster ova has been investigated. Raising the osmolarity but not the albumin concentration of the media was found to significantly increase the proportion of spermatozoa exhibiting an acrosome reaction and penetrating hamster ova, without influencing motility. There was, however, no correlation between the size of the acrosome reacted population and penetration rates between samples, suggesting that the zona-free hamster egg penetration test is more than just a measure of the availability of acrosome reacted cells. As a result of this study, a revised protocol for the hamster egg assay is described which is shorter and considerably more sensitive than conventional procedures.

Premonitory symptoms of stroke in evolution to the locked-in state

Three patients, who subsequently developed the locked-in state characterised by quadriplegia and mutism with an alert sensorium, initially had mild dysarthria and uncrossed hemisensory or hemimotor deficits involving the face and ipsilateral extremities. Case one initially mimicked a left cerebral lesion with right hemisensory deficits, a mild right facial paresis and a right homonymous field deficit. Case two initially developed both left hemimotor and hemisensory deficits and later developed a paresis of right conjugate gaze. Case three presented with left hemimotor deficit, and mild paresis of conjugate gaze to the right. All three patients died. Rostral brainstem infarctions were found at necropsy in cases one and two. Case three had a radiolucent area of the brainstem demonstrated by CT Scan. Hemisensory and hemimotor deficits also have been noted to precede reported cases of pontine infarction with the locked-in state. Acute onset of uncrossed hemisensory and hemimotor deficits with dysarthria may be caused by infarction of the pons which may predispose to the locked-in state.

The application of enzyme immunoassay to the study of salivary IGA

In the study of salivary IgA, solid-phase enzyme immunoassay has been able to show that 1) the assay is reliable, 2) minimal loss of IgA occurs from centrifuging or by elimination of insoluble mucins, 3) IgA can be easily measured in fractions from sucrose gradient sedimentation, 4) freezing alone is sufficient to preserve salivary IgA, 5) the concentration in normal saliva in 11 persons ranged from 15 to 240 mg/L (-/x = 81), and 6) an abnormal saliva contained less than 6 ug/L, the detection limit for this EIA.

Purification and partial characterization of hyaluronidase from five pace snake (Agkistrodon acutus) venom

A hyaluronidase (EC 3.2.1. 35) was isolated and purified from Agkistrodon acutus venom. The purification procedure included CM-Sephadex C-50 chromatography, gel-filtration on Sephadex G-75 and CM-Sephadex C-25 chromatography. The purified preparation of the enzyme was homogeneous on polyacrylamide gel electrophoresis at pH 4.3, a 45-fold purification being obtained. The hyaluronidase was a glycoprotein (positive PAS staining) with a molecular weight of 33,000 and a pI of 10.3. No hemorrhagic activity was found. The hyaluronidase had an optimum pH of 3.5-5.0 and an optimum temperature of 37 degrees C. It was heat sensitive, was more stable in the acidic than in the neutral region, and lost its activity in the alkaline region. Fe2+, Cu2+ and heparin inhibited the venom hyaluronidase. The Km value for hyaluronic acid was 6.2 X 10(-3) mg/ml.

The action of six antagonists of the excitatory amino acids on neurones of the rat spinal cord

The differential susceptibility to blockade by six antagonists of the excitatory actions produced by a number of acidic amino acids has been determined. Four of these, DL-alpha-aminoadipate, 2-amino-5-phosphonovalerate, 2-amino-6-phosphonocaproate and gamma-D-glutamylglycine block the action of N-methyl-D-aspartate (NMDA) most effectively and those of L-glutamate, trans-1-amino-1,3-dicarboxycyclopentane (trans-ADCP) and kainate the least. Cis-2,3-piperidine dicarboxylate resembles the other four, save in that kainate excitations are also powerfully blocked. L-glutamate diethylester was most effective against L-glutamate and least against NMDA: kainate and trans-ADCP excitations were also relatively unaffected. The data support the hypothesis of the existence of at least three classes of amino acid receptor (NMDA-, L-glutamate- and kainate-excited), and the possibility of a fourth category activated by trans-ADCP must be considered.

Cerebral edema and ophthalmoplegia reversed by mannitol in a new case of insulin-dependent diabetes mellitus

Cerebral edema is a sometimes fatal complication of diabetic ketoacidosis which occurs unpredictably and when biochemical parameters show improvement. A case of a young, newly diagnosed insulin-dependent diabetic boy who developed this complication while receiving a low-dose continuous insulin infusion is reported. Two hours after treatment signs of headache, ophthalmoplegia, and blurred disc margins suggested early cerebral edema. Despite fluid restriction, avoidance of alkali, and phosphate supplementation, cerebral edema ensued three hours later. This complication was then reversed by administration of mannitol. Our patient's ophthalmoplegia, unlike typical diabetic ophthalmoplegia, improved immediately and completely resolved within two weeks after this episode. It is concluded that the use of mannitol in the cerebral edema of diabetic ketoacidosis is beneficial if it is instituted promptly.

Interaction of myosin subfragment 1 with Cibacron Blue F3GA

Cibacron Blue F3GA and its immobilized derivatives have been shown before to bind and inhibit nucleotide-dependent enzymes and, among them, myosin subfragment 1. Experiments have been carried out to examine the mechanism of the subfragment 1--dye interaction. Binding of subfragment 1 to immobilized dye (Affi-Gel Blue) does not involve the ATP binding site on myosin. Subfragment 1 hydrolyzes MgATP and CaATP while bound to the Affi-Gel Blue column. Inactivated subfragment 1, which contains [3H]ADP noncovalently trapped at the active site, binds and elutes from the Affi-Gel Blue column in the same manner as unmodified, active protein. Free Cibacron Blue inhibits the ATPase activity of subfragment 1. The inhibition is pH, salt, and time dependent. Complete inhibition correlates with the noncovalent binding of four to five dye molecules per mole of subfragment 1. Three to four of these dye molecules can be preferentially removed from subfragment 1 in the presence of 1 M KCl without relieving the inhibition. This inhibition, which can be traced to one dye molecule per subfragment 1, is reversible and is facilitated in the presence of MgADP and MgATP, suggesting that the dye does not bind at the active site of subfragment 1. Our observations are explained in terms of hydrophobic and electrostatic protein--dye interactions.

Solid-phase selection of human T lymphocyte subpopulations using monoclonal antibodies

This report describes a novel solid-phase technique for the positive selection of human T lymphocyte subsets labeled by indirect immunofluorescence with monoclonal anti-bodies. Fluorescein labeled normal human T cells or a T cell line were fractionated on plastic culture dishes precoated with affinity chromatography purified anti-fluorescein antibodies. Cell binding was specific for fluorescein, and was both time and temperature dependent. Bound cells were eluted at 37 degrees C with fluorescein-L-lysine. The eluted cells were enriched with highly viable and functional human T cell subsets. Thus Leu3 monoclonal antibody selected cells were shown to provide helper activity in the pokeweed mitogen induced IgM and IgG immunoglobulin secretory response of autologous B cells. The Leu2 antibody selected T cells suppressed both IgM and IgG secretory responses. In addition, studies with the monoclonal antibody 1G11, which binds to an antigen expressed on acute lymphocytic leukemia (T-ALL) cells and the T-ALL derived cell line RPMI-8402, demonstrated that this solid-phase technique can be used to select for cells which are present at low frequencies in a mixed population. It thus provides a simple and reproducible means for the preparative isolation of lymphocyte subsets associated with autoimmune and neoplastic disease for functional and biochemical analysis.

Comparative pharmacokinetics of 1-(2-chloroethyl)-3-(2,6-dioxo-1-piperidyl)-1-nitrosourea in rats and patients and extrapolation to clinical trials

The plasma pharmacokinetics of 1-(2-chloroethyl)-3-(2,6-dioxo-1-piperidyl)1-nitrosourea (PCNU) were determined in ambulatory rats and in patients receiving PCNU chemotherapy in Phase 1 and II studies. After derivativization to the methyl carbamate, both rat and human PCNU plasma levels were measured by gas chromatography-mass spectrometry. Comparison of the tolerated dose levels and pharmacokinetics of PCNU to the values determined for 1,3-bis(2-chloroethyl)-1-nitrosourea in humans indicated that PCNU has a lower plasma drug area under the curve at equitoxic doses. We conclude that PCNU may show less clinical efficacy than 1,3-bis(2-chloroethyl)-1-nitrosourea in the treatment of solid tumors.

Lymphocytotoxic anti-LewisbH antibody

We wish to report strong lymphocyte crossmatch incompatibility attributable to anti-Lea antibody. The prospective renal transplant recipient was Le(a-b-) and her serum contained potent anti-Lea and anti-LebH antibodies. Despite the fact that were able to demonstrate greater B lymphocyte than T lymphocyte Lewis(a+) antigenicity, this serum was capable of causing greater than 80% cytotoxicity of Le(a+) and Le(b+)O or A2 whole lymphocyte populations. Antibody activity was completely inhibited by Lewis substance. This inhibition was specific and did not interfere with HLA antibody activity.

The postexcitatory effects of acidic amino acids on spinal neurones

The excitation of some neurones in the spinal cord of rats by L-glutamate and L-aspartate is followed by a period of reduced excitability. This effect is not observed after excitation by D-glutamate nor, in the case of Renshaw cells, by acetylcholine. The depressions following L-glutamate were reduced by bicuculline and those after aspartate by strychnine, suggesting that they may have been caused through decarboxylation of the excitatory amino acids to yield the inhibitory compounds gamma-aminobutyric acid and beta-alanine, respectively.