Novice providers' success in performing lumbar puncture: a randomized controlled phantom study between a conventional spinal needle and a novel bioimpedance needle

BACKGROUND

Lumbar puncture (LP) is an important yet difficult skill in medical practice. In recent years, the number of LPs in clinical practice has steadily decreased, which reduces residents' clinical exposure and may compromise their skills and attitude towards LP. Our study aims to assess whether the novel bioimpedance needle is of assistance to a novice provider and thus compensates for this emerging knowledge gap.

METHODS

This randomized controlled study, employing a partly blinded design, involved 60 s- and third-year medical students with no prior LP experience. The students were randomly assigned to two groups consisting of 30 students each. They performed LP on an anatomical lumbar model either with the conventional spinal needle or the bioimpedance needle. Success in LP was analysed using the independent samples proportion procedure. Additionally, the usability of the needles was evaluated with pertinent questions.

RESULTS

With the conventional spinal needle, 40% succeeded in performing the LP procedure, whereas with the bioimpedance needle, 90% were successful (p < 0.001). The procedures were successful at the first attempt in 5 (16.7%) and 15 (50%) cases (p = 0.006), respectively. Providers found the bioimpedance needle more useful and felt more confident using it.

CONCLUSIONS

The bioimpedance needle was beneficial in training medical students since it significantly facilitated the novice provider in performing LP on a lumbar phantom. Further research is needed to show whether the observed findings translate into clinical skills and benefits in hospital settings.

Incidence of Traumatic Lumbar Punctures in Neonates and Infants

OBJECTIVES

 The objective of this study is to examine factors accounting for the incidence of traumatic lumbar puncture (TLP) in infants younger than 1 year old.

STUDY DESIGN

 Retrospective analysis of cerebrospinal fluid (CSF) data from 1,240 neonatal (≤28 days) and 399 infant lumbar puncture (LP) procedures was conducted. Data from two successive LP procedures were obtained from 108 patients. Logistic regression analysis was used to assess factors accounting for the incidence of TLP in the second LP procedure. The following categorical variables were entered into the model: whether the first procedure was traumatic according to criteria of ≥500 and ≥10,000 erythrocytes/µL, whether the LP procedures were performed within a week, and whether the patient was neonatal at the first procedure.

RESULTS

 The incidences of TLP were 42.9% in neonates and 22.5% in infants for the criterion of ≥500 erythrocytes/µL, and 16.6 and 10.3% for the criterion of ≥10,000 erythrocytes/µL. Compared with a nontraumatic first LP procedure, if the first procedure was traumatic according to the criterion of ≥10,000 erythrocytes/µL, the odds ratio (OR) of TLP in the second procedure was 5.86 (p = 0.006). Compared with a longer time, if the successive procedures were performed within a week, the OR of TLP was 9.06 (p < 0.0001) according to the criteria of ≥500 erythrocytes/µL and 3.34 (p = 0.045) according to the criteria of ≥10,000 erythrocytes/µL. If the patient was neonatal at the first procedure, the OR of TLP at the second puncture was 0.32 (p = 0.031) according to the criterion of ≥500 erythrocytes/µL.

CONCLUSION

 The incidence of TLP in neonates is twice as high as that in infants. Successive LP procedures performed within a week and a highly blood-contaminated CSF sample in the first procedure each multiplied the odds of TLP in the second procedure, whereas being a neonate at the time of the first procedure reduced the odds of TLP.

KEY POINTS

· Traumatic LPs increase diagnostic uncertainty.. · Traumatic LPs are twice as common in neonates as in infants.. · Two LPs performed within a week multiplied the odds of traumatic LP.. · Erythrocyte-based criteria for traumatic LP affect the incidence of TLP..

Finnish children who needed long-term home respiratory support had severe sleep-disordered breathing and complex medical backgrounds

AIM

No studies have described long-term paediatric home respiratory support in Nordic countries. We examined the clinical characteristics and long-term outcomes of paediatric patients who received continuous positive airway pressure, non-invasive-positive-pressure ventilation and invasive ventilation from a multidisciplinary home respiratory support team.

METHODS

Retrospective tertiary-level data were collected between 1 January 2010 and 31 December 2020 in Tampere University Hospital. These comprised patient demographics, treatment course and polysomnography-confirmed sleep-disordered breathing (SDB).

RESULTS

There were 93 patients (63.4% boys). The median age at treatment initiation was 8.4 (range 0.11-16.9) years. The patients had: neuromuscular disease (16.1%), central nervous system disease (14.0%), developmental disabilities and congenital syndrome (29.0%), lung-airway conditions (11.8%), craniofacial syndrome (15.1%) and severe obesity (14.0%). More than two-thirds had severe SDB (66.7%) and the most common one was obstructive sleep apnoea in 66.7%. We found that 92.5% received long-term therapy for more than 3 months and the mean treatment duration was 3.3 ± 2.7 years. A non-invasive mask interface was used in 94.7% of cases and 5.3% needed tracheostomy ventilation. More than a quarter (26.7%) achieved disease resolution during the study period.

CONCLUSION

Most children who needed long-term home respiratory support had complex conditions and severe, persistent SDB.

Incidence of traumatic lumbar punctures in adults: the impact of a patient's first procedure

INTRODUCTION

Lumbar puncture (LP) is a widely used diagnostic method in patients of all ages. Blood-contaminated cerebrospinal fluid samples are frequent and may compromise diagnostic accuracy.

OBJECTIVES

We determined age-specific incidences of traumatic LPs (TLPs) in adults and examined factors that accounted for the incidence of TLPs.

METHODS

Erythrocyte count data from 15,812 LP procedures (2,404 were performed twice) were collected from hospital records of patients aged from 18 to 104 years. The incidence of TLPs in a patient's second LP procedure was evaluated with logistic regression analysis using the first LP, the time between the procedures and age as predictors.

RESULTS

The incidence of TLP in the second procedure was at least double that in the first procedure. If the first procedure was traumatic, the odds ratio of a TLP in the second procedure was 7-40-fold. One day between the successive procedures was associated with an over 10-fold odds ratio increase of TLP, and a week was still 4-8-fold odds ratio increase. Age was also associated with the incidence of TLP.

CONCLUSIONS

Two factors (a week or less between a patient's two LP procedures or a traumatic first LP) multiply the odds of the second procedure being traumatic and contribute to whether a patient's following LP procedure is successful.

Traumatic lumbar punctures in diagnostic and intrathecal treatment punctures of pediatric hemato-oncology patients

Successful first diagnostic lumbar puncture (LP) is crucial because intrathecal chemotherapy has not yet protected the central nervous system against cancer cells. If blood contaminates the cerebrospinal fluid (CSF) with blasts, they may enter the central neural system and compromise the patient's health. We retrospectively determined the incidence of traumatic lumbar punctures (TLP) in 2,507 LPs of 250 pediatric hemato-oncology patients aged from one to 18 years, including both diagnostic and intrathecal treatment procedures, and 2,617 LPs of 1,525 other age-matched pediatric patients. We used ≥10 erythrocytes/µL in the CSF sample as the criterion of TLP. TLPs were less frequent in hemato-oncology patients than in other patients (31.6% vs. 48.5%, p < 0.0001). The incidence of TLP was significantly lower in the first diagnostic LP than in subsequent intrathecal treatment LPs (20.5% vs. 31.6%, p = 0.0046). According to logistic regression analysis, the odds of TLP was 1.6-fold if the LP procedure was not performed in the hemato-oncology department. The odds of the patient's next LP being traumatic were threefold if the previous first LP was traumatic. A week or less time between the first and next LP tripled the odds of TLP as well. The patient's age category was not significantly associated with the incidence of TLP. Given the risks of TLP, hemato-oncology patients' first diagnostic LP should include administration of chemotherapy, as generally recommended, and be performed under general anesthesia or deep sedation by an experienced physician to optimize not only the success of the first LP procedure but also following procedures.

Most adder bites in Finland's Lake District caused mild symptoms and severe poisoning was rare

AIM

This study investigated the incidence, clinical picture and treatment of paediatric adder bites in Finland's Lake District.

METHODS

Data were retrospectively collected on all children aged 0-15 years who were bitten by adders from 2006 to 2015 and treated at Tampere University Hospital. The severity was evaluated with the five-level Poisoning Severity Score.

RESULTS

We found that 109 children were treated following an adder bite, which was an incidence of 13 per 100,000 children from 0 to 15. Of these, 75 were under 8 years of age, with a median age of 3.5 years, and 34 were 8-15 years, with a median age of 10.3 years. The gender distribution was similar in both ages. Younger children were more likely to be bitten in their yards at home, whereas older children were more likely to be bitten in a forest. Older children reported more pain than younger patients. Most children were bitten on a lower limb, with minor symptoms such as localised redness and swelling, and received conservative treatment. Antivenom treatment was rarely administered and then only in severe cases or if symptoms progressed.

CONCLUSION

Adder bites mostly caused mild symptoms, severe poisoning was rare and antivenom was rarely given.

Real-time detection of cerebrospinal fluid with bioimpedance needle in paediatric lumbar puncture

Background

Lumbar puncture is a common clinical procedure that can occasionally be difficult. Various needle guidance methods can facilitate performing this procedure, but at the expense of special expertise, equipment and facility. In the present study, we evaluated the clinical feasibility of a novel bioimpedance needle system regarding its ability to detect cerebrospinal fluid (CSF) in paediatric lumbar punctures.

Methods

We performed 40 lumbar puncture procedures using the bioimpedance needle system in 37 paediatric patients, aged from 0 days to 17 months, as a part of their prescribed examinations in two university hospitals. The bioimpedance needle is similar to a conventional 22G cutting‐edge spinal needle with a stylet, except the needle and stylet are configured as a bipolar electrode with high spatial resolution. The system measures in real‐time when the needle tip reaches the subarachnoid space containing CSF. The procedure was considered successful when the erythrocyte count was determined from the obtained CSF sample.

Results

Subarachnoid space was verifiably reached in 28 out of 40 procedures (70%). Bioimpedance needle system detected CSF in 23 out of these 28 successful procedures (82%) while failed in 3 out of 28 procedures (11%). No adverse events were reported.

Conclusion

Bioimpedance spinal needle system was found clinically feasible in paediatric lumbar punctures, and it may offer an objective and simple means to detect the time point when the needle tip is in contact with the cerebrospinal fluid.

Cryopyrin-associated periodic syndrome in early childhood can be successfully treated with interleukin-1 blockades

Cryopyrin-associated periodic syndrome (CAPS) is caused by a mutation in the NLRP3 gene encoding cryopyrin production. Overproduction of interleukin-1 (IL-1) leads to symptoms that are associated with elevated inflammatory markers, including periodic fever and a rash. We provide a clinical overview of CAPS in children, including three Finnish case studies.

CONCLUSION

When CAPS has been diagnosed, an IL-1 blockade with biological should be introduced to lessen the symptoms and to prevent the progression of organ damage.

Severe Lower Respiratory Tract Infection Caused by Human Bocavirus 1 in an Infant

We report a case of human bocavirus 1 (HBoV1) bronchiolitis that led to life-threatening respiratory failure in a 9-month-old boy with no other pathogens detected. The virus-specific diagnosis was confirmed with the detection of HBoV1 DNA in respiratory samples and both DNA and IgM and IgG to HBoV1 in serum samples.

Avoidance of Cow's Milk-Based Formula for At-Risk Infants Does Not Reduce Development of Celiac Disease: A Randomized Controlled Trial

BACKGROUND & AIMS

Feeding during the first months of life might affect risk for celiac disease. Individuals with celiac disease or type 1 diabetes have been reported to have high titers of antibodies against cow's milk proteins. Avoidance of cow's milk-based formula for infants with genetic susceptibility for type 1 diabetes reduced the cumulative incidence of diabetes-associated autoantibodies. We performed a randomized controlled trial in the same population to study whether weaning to an extensively hydrolyzed formula reduced the risk of celiac disease autoimmunity or celiac disease.

METHODS

We performed a double-blind controlled trial of 230 infants with HLA-defined predisposition to type 1 diabetes and at least 1 family member with type 1 diabetes. The infants were randomly assigned to groups fed a casein hydrolysate formula (n = 113) or a conventional formula (control, n = 117) whenever breast milk was not available during the first 6-8 months of life. Serum samples were collected over a median time period of 10 years and analyzed for antibodies to tissue transglutaminase (anti-TG2A) using a radiobinding assay, to endomysium using an immunofluorescence assay, and antibodies to a deamidated gliadine peptide using an immunofluorometry assay. Duodenal biopsies were collected if levels of anti-TG2A exceeded 20 relative units. Cow's milk antibodies were measured during the first 2 years of life.

RESULTS

Of the 189 participants analyzed for anti-TG2A, 25 (13.2%) tested positive. Of the 230 study participants observed, 10 (4.3%) were diagnosed with celiac disease. We did not find any significant differences at the cumulative incidence of anti-TG2A positivity (hazard ratio, 1.14; 95% confidence interval, 0.51-2.54) or celiac disease (hazard ratio, 4.13; 95% confidence interval, 0.81-21.02) between the casein hydrolysate and cow's milk groups. Children who developed celiac disease had increased titers of cow's milk antibodies before the appearance of anti-TG2A or celiac disease.

CONCLUSIONS

In a randomized controlled trial of 230 infants with genetic risk factors for celiac disease, we did not find evidence that weaning to a diet of extensively hydrolyzed formula compared with cow's milk-based formula would decrease the risk for celiac disease later in life. Increased titers of cow's milk antibody before anti-TG2A and celiac disease indicates that subjects with celiac disease might have increased intestinal permeability in early life. ClinicalTrials.gov Number: NCT00570102.

Spontaneous pneumomediastinum in an 11-year-old boy after a shallow breath-hold dive

Spontaneous pneumomediastinum is caused by pulmonary barotrauma due to transiently increased intra-alveolar and intra-bronchial pressure. The most frequent triggers of spontaneous pneumomediastinum in children are asthma and manoeuvres creating forced expiration. It has been rarely associated with breath-hold diving. Chest pain and dyspnoea are the main symptoms, and the diagnosis can be confirmed by chest X-ray. The treatment of choice is oxygen, analgesics and monitoring the patient. The recurrence rate is low. The main differential diagnoses of spontaneous pneumomediastinum are oesophageal perforation and pericarditis. We report a case of an 11-year-old boy with no substantial medical history, who tried to breath-hold in shallow water for as long as possible. After diving, he felt dyspnoea and chest pain. Chest X-ray revealed pneumomediastinum and subcutaneous emphysema. The patient was admitted to the PICU for observation and was discharged after two days' follow up. Spontaneous pneumomediastinum in children may be more common than thus far acknowledged. It requires a high index of suspicion and should be considered in all children with acute chest pain.

[Bronchiolitis]

Bronchiolitis is the most common disease leading to hospitalization of infants of less than one year of age in Finland. Among each age group, the disease needs hospitalization in approx. 3% of the cases. Patients of less than one month of age and formerly premature infants, especially those having bronchopulmonary dysplasia, require intensive care. Monitoring of oxygenation and administration of supplemental oxygen are the cornerstones of the treatment. When required, inhalations of racemic epinephrine are given for severe symptoms. The authors' treatment practice for bronchiolitis is presented in this article.

[Recurrent pneumonia in a teenage boy]

Pneumonia is a common paediatric and juvenile infection, which upon proper treatment will almost always heal completely. Sometimes pneumonia will become prolonged or recur, causing the need to consider additional investigations. Refractory or recurrent pneumonia in children may be caused by a structural, functional or immunological factor. Diseases of the lung tissue are rare. We describe a teenage boy, whose recurrent pneumonia revealed an underlying malignant disease, mucoepidermioid carcinoma.

[Seizures in newborn infant]

Seizures in newborn infants are common. The may constitute a neurologic emergency or a nonepileptic, harmless symptom. Diagnostics is becoming more specific with current methodologies. Detailed description of seizures and their connection with EEG abnormalities are the diagnostic cornerstones. The treatment has made slow progress, but newer antiepileptic drugs may aid in the treatment of epileptic seizures in newborn infants in the future. For the time being, evidence-based research results for them are lacking, as well as data on long-term effects. Differential diagnosis of seizures has become increasingly important.

Impaired adrenocortical function in very low birth weight infants after multiple pregnancies

OBJECTIVE

To evaluate the differences in adrenal function between very low birth weight (VLBW) infants from singleton and multiple pregnancies.

DESIGN AND METHODS

Forty infants of birth weights less than 1500 g underwent an ACTH test. Thirty infants born from singleton pregnancies (singleton group) and ten born from multiple pregnancies (multiple group) were enrolled. A baseline blood sample was drawn for cortisol measurement and thereafter serum cortisol was measured 1 and 2 h after an i.v. injection of ACTH.

RESULTS

In multiple pregnancies, the median basal cortisol level of the infants was significantly lower than that in the singletons. The median cortisol level at 1 and 2 h after administration of ACTH was significantly lower in infants from multiple gestations than in singletons. Of infants from the multiple gestation group six, and of the singleton infants 12, had baseline cortisol levels lower than the reference values (P=0.48). One hour after ACTH stimulation all multiple and 53% of the singleton group infants showed a subnormal (<500 nmol/l, P=0.007) cortisol response. Two hours after ACTH, nine multiple group patients and 43% of the singletons had subnormal (<500 nmol/l, P=0.01) stimulated cortisol levels.

CONCLUSIONS

We have concluded that VLBW infants from multiple gestations seem to be at an increased risk of insufficient postnatal adrenocortical function. In the future, specific attention should be paid to evaluate further newborn infants from multiple pregnancies with regard to a possible benefit of hydrocortisone substitution in stressful clinical situations.

Increased frequency of islet cell antibodies in unaffected brothers of children with type 1 diabetes

AIM

To assess the relation between islet cell antibody (ICA) positivity and demographic characteristics in an extensive series of first-degree relatives of children with type 1 diabetes (T1D).

METHODS

Family members of children diagnosed with T1D before the age of 16 years and attending one of 27 participating paediatric units in Finland taking care of children with diabetes were invited to volunteer for an ICA screening program aimed at identifying individuals eligible for inclusion in the European Nicotinamide Diabetes Intervention Trial (ENDIT). The final series comprised 2,522 first-degree relatives (1,107 males) with a mean age of 20.4 (range 0.1-51.9) years, out of whom 390 were fathers, 622 mothers, 717 brothers, and 793 sisters of affected cases.

RESULTS

Two hundred and four family members (8.1%) tested positive for ICA with levels ranging from 3 to 564 (median 18) Juvenile Diabetes Foundation (JDF) units. One hundred and five relatives (4.2%) had an ICA level of 18 JDF units or more. Males had detectable ICA more often than females (9.6 vs. 6.9%; p = 0.02). Antibody-positive family members under the age of 20 years had higher ICA levels than the older ones [median 18 (range 3-514) JDF units vs. 10 (range 3-564) JDF units; p = 0.008]. Among the adult relatives (>or=20 years of age) antibody-positive females had higher ICA levels than the males [median 10 (range 5-564) JDF units vs. 9 (range 3-130) JDF units; p = 0.04]. Siblings had an increased frequency of high-titre ICA (>or=18 JDF units) when compared to the parents (4.8 vs. 3.2%; p = 0.05). Among siblings, we found a higher frequency of ICA positivity in brothers than in sisters (10.8 vs. 6.9%; p = 0.01), and this was also true for high-titre ICA (6.0 vs. 3.8 %; p = 0.04). Geographically, the highest ICA prevalence was seen among relatives living in the middle of Finland (10.4 vs. 7.2% in the other parts of Finland; p = 0.01).

CONCLUSIONS

These results imply that male gender and young age favour positive ICA reactivity among family members of children with T1D. Siblings test positive for high ICA titres (>or=18 JDF units) more frequently than parents. Accordingly, judged from demographic characteristics, the yield of ICA screening in first-degree relatives would be maximized by targeting young brothers of affected cases.

Stable transfection of the rat follicle-stimulating hormone receptor complementary DNA into an immortalized murine Sertoli cell line

A plasmid expressing the rat FSH receptor (R) cDNA under the Simian virus (SV) 40 promoter/enhancer was stably transfected into a mouse Sertoli cell (SC) line (MSC-1) established from transgenic mice carrying a fusion gene of the human anti-Müllerian hormone (AMH) promoter sequences linked to the SV40 T-antigen gene (Peschon et al., 1992). The original cell line has numerous SC characteristics, but it was reported not to express the inhibin-alpha and follicle-stimulating hormone (FSH)R genes. The new FSHR expressing cell line possessed approximately 2000 per cell with equilibrium association constant (Ka) of 1.5 x 10(9) l/mol. In Northern blots, an FSHR mRNA species of 2.6 kb was found. The cells responded to recombinant human FSH (recFSH) and pertussis toxin (PT) with stimulated cAMP production. Moreover, PT enhanced the FSH-stimulated cAMP production in these cells, indicating the presence of a functional Gi protein. 12-O-tetradecanoylphorbol-13-acetate (TPA) suppressed the FSH-stimulated cAMP production of the cells, which effect was similar to that observed previously upon protein kinase C (PKC) activation in rat seminiferous tubules in vitro. Hence, the FSHR signalling, and its modulatory pathways, were intact in the FSHR expressing MSC-1 cell line. RT-PCR with inhibin-alpha specific oligonucleotide primers. followed by Southern hybridization, indicated that, unlike previously shown, the original and the FSHR expressing MSC-1 cells do express the inhibin alpha gene. FSH stimulation of the cells decreased their proliferation and, unexpectedly, the inhibin-alpha mRNA levels. The cells have functional features both from neonatal and mature SC. A feature of the former cells is the lack of FSH-stimulated up-regulation of inhibin-alpha expression; in fact FSH decreased this message. The antiproliferative, and apparently differentiating, effect of FSH on these cells resembled mature SC functions. Since adult SC do not proliferate in vitro, the new FSHR expressing and proliferating cell line provides a useful in vitro model for studying some facets of SC functions, though keeping in mind that these transformed cells do not behave identically with adult SC in vivo. The constitutive expression of FSHR in these cells allows the study of posttranscriptional events in the FSHR regulation.

Lack of endogenous adenosine receptor activation explains the insensitivity of neonatal rat Leydig cells to treatment with pertussis toxin

We have previously shown that the Gi protein-mediated negative modulation of FSH-stimulated cAMP production in neonatal rat Sertoli cells can be blocked by pretreatment with pertussis toxin (PT), an inhibitor of the Gi protein function. In contrast, hCG-stimulated testosterone (T) production by neonatal Leydig cells was insensitive to PT action, despite the demonstration of Gi protein in these cells by immunohistochemistry. We now tested the hypothesis that the missing Gi protein function in neonatal Leydig cells is due to absence of its endogenous activator, adenosine. It was first reconfirmed in dispersed cells of 7-day-old rats that PT preincubation enhanced FSH-stimulated cAMP production (i.e. Sertoli cell function), but had no effect on hCG-stimulated T production (Leydig cell function). The adenosine agonist n-phenylisopropyladenosine (PIA 1 mumol/l), acting through the Gi-protein, attenuated FSH-stimulated cAMP production, and this effect was abolished when the Gi protein was inactivated by preincubation with PT. PIA (1 mumol/l) also inhibited (P < 0.05-0.01) the basal and hCG-stimulated rates of Leydig cell T production, and the PIA effect was abolished by PT preincubation. In conclusion, the present data show that the apparent absence of a functional Gi protein function of neonatal Leydig cells is due to insufficient endogenous levels of the stimulating ligand, adenosine. When the Gi protein function is activated by exogenous adenosine agonist (PIA), the enhancement of hCG-stimulated T production by PT can be demonstrated. At the same time, the endogenous level of adenosine is sufficient for activation of the Gi protein function in Sertoli cells.

A novel role for testicular descent; temperature-dependent induction of pertussis toxin-sensitive Gi protein function in postnatal rat Leydig cells

The role of temperature and testicular descent in postnatal appearance of inhibitory guanine nucleotide-binding regulatory protein (G(i)) function was studied in the rat testis. Dispersed testicular cells of 5-day-old rats were incubated for 24 h at 32 or 37 C, then for another 24 h at the same temperatures in the presence and absence of pertussis toxin (PT; 100 micrograms/liter), and finally for a third 24-h period with cholera toxin (CT; 500 ng/liter) with or without PT. At both temperatures, PT treatment significantly (P < 0.05) increased the CT-stimulated cAMP output, but had no effect on basal cAMP production. When testosterone (T) production, as an indicator of Leydig cell function, was measured in the same incubation, CT-stimulated T production was greater at 32 C, but PT had no effect at either temperature. A similar finding was made when hCG (10 micrograms/liter), instead of CT, was used as the stimulus of T production. Hence, a functional G(i) protein is present in seminiferous tubules of 5-day-old testes cultured for 3 days at 32 and 37 C, but not in Leydig cells. We then examined the effects of longer exposure of 5-day-old testes to the two temperatures. After culture for 7 days with 0.1 microgram/liter ovine LH, the presence of PT at 32 C significantly (P < 0.01) enhanced CT-stimulated T production during the last 24 h of culture, but the PT effect was not observed when the culture was carried out at 37 C. Hence, G(i)-mediated modulation of Leydig cell function appears to require several days of induction at the lower temperature of 32 C. As the postnatal descent also changes the ambient testicular temperature, we next studied whether this event alters the G(i) protein function of Leydig cells. Five-day-old rats were rendered bilaterally cryptorchid or sham operated, and studied after 12 days. Testis weights did not differ between the abdominal and scrotal testes. In contrast, the basal and hCG-stimulated rates of T production were significantly (P < 0.01-0.05) higher in the scrotal testes. When dispersed cells of the scrotal and abdominal testes were incubated for 24 h at 37 C in the presence of CT with or without PT, enhancement of T production by PT was only observed in cells of the scrotal testes.(ABSTRACT TRUNCATED AT 400 WORDS)

Ontogeny of the inhibitory guanine nucleotide-binding regulatory protein in the rat testis: mRNA expression and modulation of LH and FSH action

The ontogeny of function and mRNA expression of the inhibitory guanine nucleotide-binding regulatory protein (Gi) was studied in the rat testis. Dispersed testis cells of animals aged 8, 15, 20 and 30 days were cultured with or without 100 micrograms/l pertussis toxin (PT) for 24 h. The cells were then cultured for another 24 h with medium only, cholera toxin (CT), PT, or their combination, and the amount of testosterone and cAMP production was measured. PT preincubation increased CT-stimulated cAMP production at all ages, thus indicating the presence of a functional Gi-protein in the postnatal testis. However, when testosterone production was measured, the enhancing effect of PT was absent at the age of 8 days only, indicating that Leydig cells at this age did not have functional Gi-protein. We then cultured 2-day-old and 8-11-day-old testis cells, after 24 h pretreatment with PT, in the presence of ovine follicle-stimulating hormone (FSH) (1 mg/l). The FSH-stimulated cAMP production was enhanced at both ages, thus indicating the presence of a functional Gi-protein in neonatal Sertoli cells. In Northern blot analyses, fetal and postnatal testis tissue had very similar levels of G alpha i2 and G alpha i3 mRNAs; the mRNA level of Gi1 in Northern blots remained low compared to those of Gi alpha 2 and Gi alpha 3. In conclusion, the Gi protein appears in the developing rat testis in utero but the activity first seems to be confined to non-Leydig cells including the Sertoli cell. In Leydig cells, the functional Gi-protein appears between days 8-15 post partum. This finding may be related to the fact that the fetal-neonatal population of Leydig cells possesses a high steroidogenic capacity and an apparent lack of the ability to respond to high gonadotropic stimulation with LH receptor down-regulation and steroidogenic enzyme desensitization.

Age-related variation of follicle-stimulating hormone-stimulated cAMP production, protein kinase C activity and their interactions in the rat testis

To study further the ontogeny of hormonal regulatory mechanisms in the testis, we measured follicle-stimulating hormone (FSH)- and protein kinase C (PKC)-stimulated cAMP production, PKC activity, and messenger (m)RNA levels of the PKC isoenzymes alpha, beta and gamma in rat testes between day 19 of fetal life and day 90 postpartum. Human FSH (30 mg/l) stimulated slightly but significantly cAMP production of fetal testes (57%; p < 0.05). A higher response (3-fold; p < 0.01) was observed on the day of birth, and the maximum FSH effect on cAMP (23-fold) was observed on day 10 postpartum. Thereafter, a gradual decline of FSH response occurred towards adult age. Concerning testicular PKC, the soluble (inactive) form had its maximum at the age of 1 day and this PKC form declined gradually thereafter. The particulate (active) form was low at birth, increased 6-fold on days 8-11 of age, and declined thereafter. A significant age-dependent variation was also found in the mRNA level of the PKC alpha isoenzyme (maximum on day 10), whereas those of PKC gamma and PKC beta were undetectable at all ages in Northern blots. When the in vitro modulation of basal and FSH-dependent cAMP production by the PKC activator 12-O-tetradecanoylphorbol 13-acetate (TPA, 100 nmol/l) was studied, the substance alone was without effect at all ages studied. The TPA effect on FSH-stimulated cAMP production displayed age-dependent variation: a slight stimulation in fetal testes, no effect at birth, decrease between days 8 and 11, and no effect on day 30.(ABSTRACT TRUNCATED AT 250 WORDS)

The murine luteinizing hormone and follicle-stimulating hormone receptor genes: transcription initiation sites, putative promoter sequences and promoter activity

The putative promoter regions of the murine follicle-stimulating hormone (FSH) and luteinizing hormone (LH) receptor genes were isolated and used to map transcription initiation sites for both genes. For the FSH receptor gene, a major transcription initiation site was found 534 nucleotides upstream, and for the LH receptor gene 310 nucleotides upstream of the corresponding translation initiation codons. In addition, several alternative minor transcription initiation sites were observed for both genes. The nucleotide sequences of the promoter regions revealed no canonical promoter elements, such as TATA and CCAAT consensus sites 5' of the main transcriptional start sites. The isolated promoter segments for both receptor genes showed low functional activity as verified in transient expression studies in immature rat granulosa cells using the luciferase coding region as the reporter for promoter activity. Both promoter elements seem to be still under tissue specific control, since neither LH receptor nor FSH receptor promoter activity was detectable in another cell line (CHO) investigated.