Primary hypothyroidism and human spermatogenesis

Spermatogenic function was studied in 10 patients, previously diagnosed as having primary hypothyroidism, in whom a state of hypothyroidism has been induced by discontinuation or a decrease in treatment with levothyroxine over at least one spermatogenic cycle. Most of the patients had fathered children before the study. When the results obtained in the hypothyroid state were compared with those from a group of 16 controls with proven fertility, slight anomalies were observed; these were characterized by a decrease in seminal volume (p less than 0.05), progressive forward motility (p less than 0.01), and the cumulative percentage of mobile forms (p less than 0.01). There were no anomalies in sperm density or in the percentage of spermatozoa with normal morphology. No alterations in circulating levels of testosterone and gonadotropins existed. Induction of hypothyroidism did not lead to seminal or hormonal modifications compared with the same patients in a situation of euthyroidism. Short-term postpuberal hypothyroidism did not cause seminal alterations sufficiently intense to induce male infertility.     

Binding units (BU) and the area under binding isotherms (AUI) new indices of effector-target conjugation

New methods for simplified quantitation of effector-target conjugation have been developed. The binding unit (BU) is defined as the number of target cells required to bind a specified percentage of effector cells. The number of binding units is determined from binding isotherms in which effector conjugate frequencies are measured by holding constant the number of effector cells and by varying the number of target cells. Alternately, a binding unit can be defined as the number of effector cells required to bind a specified percentage of target cells. In this case, BU is computed from binding isotherms in which target conjugate frequencies are measured at different values of effector cells by holding constant the number of target cells. Also, the area under the curve (AUI) of these isotherms is another index that can be used as an overall measure of the binding capacity in an effector-target system. The experimental values of BU and AUI determined from effector and target isotherms agree well with theoretical predictions based on our previously developed binding model (J. Immunol. Methods (1992) 155, 133–147). The relationship between BU and AUI, and procedures to determine these parameters are shown. The value of these indices to express effector-target conjugation quantitatively has been confirmed by determining the values of BU and AUI for the NK-K562 effector-target system.     

Hepatocyte paraffin 1 antibody does not distinguish primary ovarian tumors with hepatoid differentiation from metastatic hepatocellular carcinoma.

Anti-hepatocyte antibody, hepatocyte paraffin 1, is a monoclonal antibody that is highly specific for normal and neoplastic hepatocytes and that can differentiate hepatocytic from nonhepatocytic tumors. This marker has been rarely studied in extra-hepatic tumors and to our knowledge has not been investigated in ovarian tumors with hepatoid differentiation. We studied hepatocyte paraffin 1 immunoreactivity in a series of ovarian hepatoid carcinomas, ovarian hepatoid yolk sac tumors (YSTs), and hepatocellular carcinomas metastatic to the ovary to assess the potential utility of hepatocyte paraffin 1 in differential diagnosis. Hepatocyte paraffin 1 positivity was seen in three of seven ovarian hepatoid carcinomas, five of eight hepatoid yolk sac tumors, and six of eight metastatic hepatocellular carcinomas. The extent of positivity ranged from <25% to >50% of the tumor cells. There was strong coarsely granular cytoplasmic staining in all three tumor types without a distinctive staining pattern in any group. The degree of hepatic differentiation correlated with hepatocyte paraffin 1 positivity in the three groups: 83% of the well differentiated tumors, 50% of the moderately differentiated tumors, and none of the poorly differentiated tumors were positive. All ovarian hepatoid carcinomas were either immunoreactive for alpha-fetoprotein or had an elevated serum alpha-fetoprotein level; more than half of these tumors were hepatocyte paraffin 1 negative. All but one hepatocyte paraffin 1 negative hepatoid yolk sac tumor and ovarian hepatocellular carcinoma were also negative for alpha-fetoprotein. In conclusion, hepatocyte paraffin 1 is positive in primary ovarian tumors with hepatoid differentiation, with the degree of hepatocyte paraffin 1 positivity correlating with the degree of hepatoid differentiation. Hepatocyte paraffin 1, however, is not useful in distinguishing metastatic hepatocellular carcinoma from primary ovarian hepatoid carcinoma or hepatoid yolk sac tumor.     

Continuous epidural infusion of racemic methadone results in effective postoperative analgesia and low plasma concentrations

PURPOSE: To compare two protocols of epidural administration of racemic methadone for postoperative analgesia (continuous infusion and intermittent bolus), focussing on plasma concentration, analgesic efficacy and side effects. METHODS: Ninety patients undergoing abdominal or lower-limb surgery were randomly assigned to two groups in a prospective double-blind design. The continuous infusion patients (n=60) received initial doses of 3 to 6 mg followed by 6 to 12 mg by continuous infusion over 24 hr. The bolus administration patients (n=30) received repeated boluses of 3 to 6 mg of racemic methadone every eight hours. Pain intensity was assessed on a visual analog scale. Amount of supplementary analgesia was recorded, as was the incidence of side effects. Plasma methadone concentrations were determined by high performance liquid chromatography. Treatment was continued for 72 hr. RESULTS: Pain relief was good and comparable in both groups throughout the three days of treatment. No accumulation of plasma racemic methadone was observed in either group, although the concentrations were significantly higher in the bolus group. Miosis was significantly more frequent in the bolus group. CONCLUSION: Plasma methadone concentrations were significantly lower with continuous infusion. Plasma methadone accumulation, which is considered the main disadvantage for its purported influence on the incidence of side effects, did not occur at the doses used over the three days of treatment that we report.     

In vitro studies of the carotid rete mirabile of Artiodactyla

The carotid rete of Artiodactyla, an intracranial arterial plexus which supplies blood to the brain, has intrigued investigators for a long time. This study was designed to examine the responsiveness of isolated retial arteries (250-700 microns in external diameter) of goat, pig, and cattle. The findings in these arteries were compared to those observed in cerebral arteries (250-650 microns in external diameter) of the same animal species. The magnitude of the arterial responses to potassium chloride varied with the resting tension applied to the tissue. The two types of vessels exhibited similar resting tension values (0.3 g) for maximal tension development in response to potassium chloride; however, the ability of retial vessels to contract in the presence of potassium chloride was consistently smaller than that of cerebral arteries. The contractile response of retial arteries to norepinephrine (10(-9) to 10(-4) M), tyramine (10(-8) to 10(-3) M), and field electrical stimulation (2-16 Hz) was negligible. The same retial arteries exhibited dose-dependent contractions in response to 5-hydroxytryptamine (10(-9) to 10(-5) M) and histamine (10(-9) to 3 X 10(-4) M). Cerebral arteries exhibited larger responses to the vasoactive agents than retial arteries. Our findings indicate that retial arteries have a small vasomotor activity in response to adrenergic stimulation or to vasoactive agents. Therefore, the carotid rete of Artiodactyla may have a low ability to change resistance to blood flow under neural or hormonal influences.     

Choosing art as a complement to healing.

Art à la Carte is a volunteer program that enables long-term care patients to decorate their hospital room with an art print of their choice. Thirty-seven participants were interviewed to evaluate the program. The data suggest that art adds a personal touch to the sterile hospital environment, facilitates interaction between staff and patients, and provides positive distractions. Choosing a work of art also helps patients to regain a sense of control. These themes coincide with the key components of supportive health care environment. The data suggest that Art à la Carte can provide a meaningful complement to the healing process.     

Short-term outcome analysis of a randomized study comparing laparoscopic vs open colectomy for colon cancer

The authors examined the impact of the laparoscopic approach on the early outcome of resected colon carcinomas. The role of laparoscopic techniques in the treatment of colon carcinomas is questionable. Previous studies have suggested technical feasibility of surgical resections of these cancers by laparoscopic means and have implied a benefit to laparoscopic technique for patients undergoing colorectal resections. A prospective, randomized study was conducted comparing laparoscopic assisted colectomy (LAC) open colectomy (OC) for colon cancer. We present the preliminary results in relation to the short-term outcome and judge the feasibility of the laparoscopic procedure to as a way of performing accurate oncologic resection and staging. Benefit has been demonstrated with LAC in this setting. Passing flatus, oral intake, and discharge from hospital occurred earlier in LAC- than OC-treated patients The mean operative time was significantly longer in the LAC group than in the OC group. The overall morbidity was significantly lower in the LAC group. No significant differences were observed between both groups in the number of lymph nodes removed or the pathological stage following the Astler-Coller modification of the Dukes classification. The laparoscopic approach improves the short-term outcome of segmental colectomies for colon cancer. However, the further follow-up of these patients will allow us to answer in the near future whether or not the LAC may influence the long-term outcome.Presented at the annual meeting of the Society of American Gastrointestinal Surgeons (SAGES), Orlando, FL, USA, 11–14 March 1995     

Revisiting the oddball paradigm. Non-target vs neutral stimuli and the evaluation of ERP attentional effects.

We recorded topographic mapping of auditory evoked potentials (AEPs) to homogeneous series of tones delivered in the absence of any cognitive task ("neutral condition") and compared them with responses to identical stimuli when they acted as non-targets in an oddball paradigm. With respect to the neutral condition, non-target responses showed an increase in N100 amplitude which was found to depend on two different, but partially overlapping effects. The "early effect" had similar latency and topography as exogenous N100 and may reflect changes in the overall state of alertness since its amplitude declined at the end of the test. The "late effect" affected the N100s descending slope and had features consistent with those of a processing negativity. It was frontally distributed, and topographic mapping revealed a right-sided predominance. Finally, non-target responses exhibited a central positivity (P250) which did not appear in neutral AEPs. P250 shares several features, including latency, amplitude and scalp topography, with the endogenous ERP component commonly labelled "P3a". Non-target P250 could be the result of an attentional shift towards the stimuli, and reflect some aspects of the classification process. We suggest that non-target responses in simple oddball paradigms should be routinely studied along with target responses in order to improve the diagnostic capabilities of cognitive ERPs. Notably, non-target responses may help to decide whether an abnormal target-P300 is related or not to a deficit in the mobilization of attentional resources.     

Ionotropic glutamate receptor subunit distribution on hypoglossal motoneuronal pools in the rat

The expression of ionotropic glutamate receptor subunits in the motoneuronal pools of the hypoglossal nucleus was studied using specific antibodies against subunits of the -amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), kainate and N-methyl-D-aspartate (NMDA) subtypes. The highest numbers of intensely immunolabelled motoneurons were found in the dorsal tier and caudoventromedial part of the hypoglossal nucleus with all antibodies except that against the GluR1 AMPA subunit. Labelling for the GluR1 subunit was weak except for caudally located groups of motoneurons which innervate tongue muscles related to respiratory activity. By contrast, most motoneurons were intensely immunostained with antibodies against GluR2/3 and GluR4 subunits of the AMPA subtype. The low staining observed using an antibody specific for the GluR2 subunit (which prevents Ca²⁺-entry through AMPA channels) strongly suggests that AMPA receptors in hypoglossal motoneurons are Ca²⁺-permeable. Immunolabelling for the GluR5/6/7 kainate receptor subunits was found in many motoneuronal somata as well as in thin axon-like profiles and puncta that resembled synaptic boutons. Most motoneurons were intensely immunostained for the NMDA receptor subunit NR1. These results show that the hypoglossal nucleus contains five heterogeneous pools of motoneurons which innervate functionally defined groups of tongue muscles. The uneven expression of the different receptor subunits analysed here could reflect diverse phenotypic properties of hypoglossal motoneurons which might be expected to generate different patterns of motor responses under different physiological or pathological conditions.